diff --git a/COMPOSABLES.md b/COMPOSABLES.md
new file mode 100644
index 0000000..f122537
--- /dev/null
+++ b/COMPOSABLES.md
@@ -0,0 +1,399 @@
+# Supergroup Vue Composables
+
+A modular, reactive grouping utility for Vue.js applications with **full TypeScript support**. Provides powerful data grouping and hierarchical organization with Vue 3's Composition API and strong typing.
+
+## TypeScript Support
+
+Supergroup is written in TypeScript and provides complete type definitions out of the box. All composables are **fully typed with generics** that infer types from your data:
+
+```typescript
+import { ref } from 'vue';
+import { useGrouping } from 'supergroup/composables';
+
+// Define your record type
+interface Employee {
+  name: string;
+  department: string;
+  salary: number;
+  role: string;
+}
+
+const employees = ref<Employee[]>([
+  { name: 'Alice', department: 'Engineering', salary: 120000, role: 'Developer' },
+  { name: 'Bob', department: 'Engineering', salary: 150000, role: 'Lead' },
+  { name: 'Carol', department: 'Sales', salary: 90000, role: 'Rep' }
+]);
+
+// Full type inference - grouping knows about Employee type!
+const grouping = useGrouping(employees, 'department');
+
+// TypeScript knows the structure
+const engineering = grouping.lookup('Engineering');
+// engineering is typed as GroupValue<Employee> | undefined
+
+// Field access is type-checked
+const avgSalary = engineering?.aggregate(
+  (values) => values.reduce((a, b) => a + b, 0) / values.length,
+  'salary' // TypeScript ensures 'salary' is a valid field
+);
+```
+
+### Type-Safe Dimensions
+
+Dimensions are type-checked to ensure they match your record type:
+
+```typescript
+// ✅ Valid - 'department' is a key of Employee
+useGrouping(employees, 'department');
+
+// ✅ Valid - function returning string/number
+useGrouping(employees, (emp) => emp.role);
+
+// ✅ Valid - array of dimensions
+useGrouping(employees, ['department', 'role']);
+
+// ❌ TypeScript Error - 'invalid' is not a key of Employee
+useGrouping(employees, 'invalid');
+```
+
+## Installation
+
+```bash
+npm install supergroup vue
+```
+
+## Quick Start
+
+### Basic Usage
+
+```javascript
+import { ref } from 'vue';
+import { useGrouping } from 'supergroup/composables';
+
+const data = ref([
+  { name: 'Alice', dept: 'Engineering', grade: 'A' },
+  { name: 'Bob', dept: 'Engineering', grade: 'B' },
+  { name: 'Carol', dept: 'Sales', grade: 'A' }
+]);
+
+const grouping = useGrouping(data, 'dept');
+
+// Access grouped values
+console.log(grouping.rawValues.value); // ['Engineering', 'Sales']
+
+// Each group has records
+const engineering = grouping.lookup('Engineering');
+console.log(engineering.records.length); // 2
+```
+
+### Multi-Level Grouping
+
+```javascript
+// Create hierarchical groups
+const multiGroup = useGrouping(data, ['dept', 'grade']);
+
+// Navigate the hierarchy
+const engGradeA = multiGroup.lookup(['Engineering', 'A']);
+console.log(engGradeA.records); // [{ name: 'Alice', ... }]
+```
+
+## Core Composables
+
+### `useGrouping(records, dimensions, options)`
+
+Main composable for creating reactive groups.
+
+**Parameters:**
+- `records` - Array or Ref<Array> of records to group
+- `dimensions` - String, Function, Array, or Ref for grouping dimension(s)
+- `options` - Optional configuration object
+
+**Returns:**
+- `grouped` - Computed group result
+- `rawValues` - Computed array of group values
+- `lookup(query)` - Function to find specific values
+- `leafNodes` - Computed array of leaf nodes
+- `flattenTree` - Computed flattened tree structure
+
+**Example:**
+```javascript
+const { grouped, rawValues, lookup, leafNodes } = useGrouping(
+  data,
+  ['category', 'subcategory'],
+  { 
+    excludeValues: ['Unknown'],
+    multiValuedGroup: false
+  }
+);
+```
+
+### `useGroupList(groupResult)`
+
+Provides operations on a group list.
+
+**Parameters:**
+- `groupResult` - The grouped result from useGrouping
+
+**Returns:**
+- `values` - Computed array of group values
+- `lookup(query)` - Single or path lookup
+- `lookupMany(queries)` - Multiple lookups
+- `rawValues` - Computed plain values array
+- `flattenTree` - Flattened tree structure
+- `leafNodes` - All leaf nodes
+- `nodesAtLevel(level)` - Nodes at specific depth
+- `aggregates(func, field, type)` - Apply aggregation
+- `toD3Entries()` - Convert to D3 nest format
+- `toD3Map()` - Convert to D3 map format
+
+**Example:**
+```javascript
+const list = useGroupList(grouping.grouped);
+
+// Aggregation
+const sums = list.aggregates((vals) => vals.reduce((a,b) => a+b, 0), 'amount');
+
+// D3 format conversion
+const d3Data = list.toD3Entries();
+```
+
+### `useGroupValue(value, childProp)`
+
+Work with individual group values.
+
+**Parameters:**
+- `value` - A group value object
+- `childProp` - Name of children property (default: 'children')
+
+**Returns:**
+- `children` - Computed child values
+- `hasChildren` - Computed boolean
+- `descendants` - All descendant values
+- `leafNodes` - Leaf descendant values
+- `pedigree` - Path from root to this value
+- `namePath(opts)` - String path representation
+- `dimPath(opts)` - Dimension path string
+- `aggregate(func, field)` - Aggregate this value's records
+- `pct` - Percentage of parent records
+- `previous()` - Previous sibling
+- `next()` - Next sibling
+
+**Example:**
+```javascript
+const value = grouping.lookup('Engineering');
+const valueOps = useGroupValue(value);
+
+console.log(valueOps.namePath()); // 'Engineering'
+console.log(valueOps.pct.value); // 0.66 (if 2 of 3 records)
+
+const sum = valueOps.aggregate(
+  (vals) => vals.reduce((a,b) => a+b, 0),
+  'salary'
+);
+```
+
+### `useGroupSelection(groupResult)`
+
+Manage selection state without mutating data.
+
+**Parameters:**
+- `groupResult` - The grouped result from useGrouping
+
+**Returns:**
+- `selectedValues` - Ref array of selected values
+- `selectValue(value)` - Select a value
+- `deselectValue(value)` - Deselect a value
+- `toggleValue(value)` - Toggle selection
+- `clearSelection()` - Clear all selections
+- `isSelected(value)` - Check if selected
+- `selectedRecords` - Computed array of records from selected values
+- `selectedCount` - Computed count of selections
+- `selectByFilter(fn)` - Select matching values
+- `selectLeafNodes()` - Select all leaves
+- `selectAtDepth(depth)` - Select at specific level
+
+**Example:**
+```javascript
+const selection = useGroupSelection(grouping.grouped);
+
+// Select a value
+const eng = grouping.lookup('Engineering');
+selection.selectValue(eng);
+
+// Check selection
+console.log(selection.isSelected(eng)); // true
+console.log(selection.selectedCount.value); // 1
+console.log(selection.selectedRecords.value); // All Engineering records
+
+// Select by criteria
+selection.selectByFilter(v => v.records.length > 5);
+```
+
+## Advanced Features
+
+### Reactive Updates
+
+All composables work with reactive data sources:
+
+```javascript
+const data = ref([...initialData]);
+const grouping = useGrouping(data, 'category');
+
+// Reactively updates when data changes
+data.value.push({ category: 'New', value: 100 });
+```
+
+### Custom Dimension Functions
+
+```javascript
+const grouping = useGrouping(
+  data,
+  (record) => `${record.firstName} ${record.lastName}`,
+  { dimName: 'fullName' }
+);
+```
+
+### Multi-Valued Groups
+
+Allow records to appear in multiple groups:
+
+```javascript
+const data = ref([
+  { tags: ['vue', 'javascript'], title: 'Vue Guide' },
+  { tags: ['javascript', 'node'], title: 'Node Basics' }
+]);
+
+const grouping = useGrouping(
+  data,
+  'tags',
+  { multiValuedGroup: true }
+);
+
+// 'javascript' group contains both records
+```
+
+### Working with D3.js
+
+```javascript
+const list = useGroupList(grouping.grouped);
+
+// D3 hierarchy format
+const d3Hierarchy = list.toD3Entries();
+
+// D3 map format
+const d3Map = list.toD3Map();
+```
+
+## Options
+
+### Grouping Options
+
+```javascript
+{
+  // Property name for children (default: 'children')
+  childProp: 'children',
+  
+  // Exclude specific values
+  excludeValues: ['Unknown', null],
+  
+  // Custom dimension name
+  dimName: 'MyDimension',
+  
+  // Truncate branches with empty values
+  truncateBranchOnEmptyVal: true,
+  
+  // Allow multi-valued grouping
+  multiValuedGroup: false,
+  
+  // Pre-process records before grouping
+  preListRecsHook: (records) => records.filter(r => r.active),
+  
+  // Specify if dimension is numeric
+  isNumeric: false
+}
+```
+
+## Migration from Legacy API
+
+The new composables are designed to work alongside the legacy API:
+
+### Legacy (lodash mixin):
+```javascript
+import _ from 'lodash';
+import 'supergroup/legacy';
+
+const groups = _.supergroup(data, 'category');
+groups.lookup('Engineering');
+```
+
+### New (Vue composables):
+```javascript
+import { useGrouping } from 'supergroup/composables';
+
+const grouping = useGrouping(data, 'category');
+grouping.lookup('Engineering');
+```
+
+## Vue Component Example
+
+```vue
+<template>
+  <div>
+    <h2>Groups</h2>
+    <div v-for="value in grouping.grouped.value.values" :key="value.value">
+      <div 
+        @click="selection.toggleValue(value)"
+        :class="{ selected: selection.isSelected(value) }"
+      >
+        {{ value.value }} ({{ value.records.length }} records)
+      </div>
+    </div>
+    
+    <div v-if="selection.selectedCount.value > 0">
+      Selected: {{ selection.selectedCount.value }} groups,
+      {{ selection.selectedRecords.value.length }} records
+    </div>
+  </div>
+</template>
+
+<script setup>
+import { ref } from 'vue';
+import { useGrouping, useGroupSelection } from 'supergroup/composables';
+
+const data = ref([
+  // your data
+]);
+
+const grouping = useGrouping(data, 'category');
+const selection = useGroupSelection(grouping.grouped);
+</script>
+
+<style>
+.selected {
+  background-color: #e3f2fd;
+  font-weight: bold;
+}
+</style>
+```
+
+## TypeScript Support
+
+TypeScript definitions are included:
+
+```typescript
+import { Ref } from 'vue';
+import { useGrouping } from 'supergroup/composables';
+
+interface MyRecord {
+  name: string;
+  category: string;
+  value: number;
+}
+
+const data: Ref<MyRecord[]> = ref([...]);
+const grouping = useGrouping(data, 'category');
+```
+
+## License
+
+MIT - See LICENSE file for details
diff --git a/README.md b/README.md
index b0e2a56..2a1a52d 100644
--- a/README.md
+++ b/README.md
@@ -1,6 +1,50 @@
 Supergroup
 ==========
-Supergroup performs single- or multi-level grouping on collections of records. It provides a host of utitily and conveniece methods on the returned array of group values as well as on each of these specific group values. If a multi-level grouping is performed, each value's `children` array also acts as a Supergroup list.
+
+> **🎉 New in v2.0:** Vue 3 Composables with Full TypeScript Support! See [COMPOSABLES.md](COMPOSABLES.md) for the new reactive, modular API.
+
+Supergroup performs single- or multi-level grouping on collections of records. It provides a host of utility and convenience methods on the returned array of group values as well as on each of these specific group values. If a multi-level grouping is performed, each value's `children` array also acts as a Supergroup list.
+
+## Installation
+
+```bash
+npm install supergroup
+```
+
+## Two Ways to Use Supergroup
+
+### 1. Vue 3 Composables (New! ✨ TypeScript ✨)
+
+Modern, reactive, **strongly-typed** API for Vue.js applications:
+
+```typescript
+import { ref } from 'vue';
+import { useGrouping, useGroupList } from 'supergroup/composables';
+
+interface MyRecord {
+  name: string;
+  dept: string;
+  value: number;
+}
+
+const data = ref<MyRecord[]>([
+  { name: 'Alice', dept: 'Engineering', value: 100 },
+  { name: 'Bob', dept: 'Sales', value: 200 }
+]);
+
+// Type inference - grouping is typed to MyRecord
+const grouping = useGrouping(data, 'dept');
+const list = useGroupList(grouping.grouped);
+
+// Reactive and type-safe!
+data.value.push({ name: 'Carol', dept: 'Engineering', value: 150 });
+```
+
+**[📖 Full Composables Documentation](COMPOSABLES.md)**
+
+### 2. Legacy API (Lodash Mixin)
+
+Original API, still fully supported:
 
 Supergroup is implemented as an Underscore or LoDash mixin, so just include one of those first:
 
@@ -115,3 +159,24 @@ just leaf nodes:
             "2":[{"A":[1,2]},{"A":[2,3]}],
             "3":[{"A":[2,3]}]
            }
+
+---
+
+## Modern Vue.js Usage
+
+Looking to use Supergroup in a Vue.js application? Check out the new **[Vue 3 Composables API](COMPOSABLES.md)** which provides:
+
+- ✨ **Reactive grouping** - Automatically updates when data changes
+- 🧩 **Modular design** - Use only what you need
+- 🎯 **Type-safe** - Built with TypeScript support in mind
+- 🔄 **Composable patterns** - Follows Vue 3 best practices
+
+```javascript
+import { useGrouping, useGroupSelection } from 'supergroup/composables';
+
+// Reactive, modular, powerful!
+const grouping = useGrouping(data, ['category', 'subcategory']);
+const selection = useGroupSelection(grouping.grouped);
+```
+
+**[Get started with Vue Composables →](COMPOSABLES.md)**
diff --git a/REFACTOR_SUMMARY.md b/REFACTOR_SUMMARY.md
new file mode 100644
index 0000000..566d7da
--- /dev/null
+++ b/REFACTOR_SUMMARY.md
@@ -0,0 +1,189 @@
+# Supergroup v2.0 - Vue.js Composables Refactor
+
+## Summary
+
+Successfully refactored the supergroup library to provide modern, reactive, modular Vue.js composables while maintaining 100% backward compatibility with the legacy lodash mixin API.
+
+## What Was Done
+
+### 1. New Vue 3 Composable API
+
+Created four main composables that provide reactive, modular grouping functionality:
+
+#### `useGrouping(records, dimensions, options)`
+- Core reactive grouping with single or multi-level hierarchies
+- Automatically updates when source data changes
+- Supports all original grouping features (multiValuedGroup, excludeValues, etc.)
+
+#### `useGroupList(groupResult)`
+- Operations on group lists (lookup, sorting, aggregation)
+- D3 format conversion (toD3Entries, toD3Map)
+- Tree navigation (flattenTree, leafNodes, nodesAtLevel)
+
+#### `useGroupValue(value, childProp)`
+- Individual value operations
+- Path computation (namePath, dimPath, pedigree)
+- Aggregation and percentage calculations
+- Sibling navigation
+
+#### `useGroupSelection(groupResult)`
+- Reactive state management without mutation
+- Select/deselect by value or filter
+- Highlight management for UI interactions
+- Computed selected records
+
+### 2. Architecture Improvements
+
+- **Modular Structure**: Separated concerns into composables and utilities
+- **Dual Module Support**: 
+  - ES modules in `src/` for modern import syntax
+  - CommonJS `supergroup.cjs` for legacy require()
+  - package.json exports support both seamlessly
+- **Reactive by Default**: All composables use Vue 3's reactivity system
+- **Tree-Shakeable**: Import only what you need
+
+### 3. Testing
+
+- ✅ All 30 existing legacy tests pass
+- ✅ 13 new composable tests validate:
+  - Basic grouping
+  - Multi-level hierarchies
+  - Lookup operations
+  - Tree navigation
+  - Selection management
+  - **Reactivity** (critical for Vue apps)
+- ✅ No security vulnerabilities (CodeQL verified)
+
+### 4. Documentation
+
+- **COMPOSABLES.md**: Comprehensive API documentation with examples
+- **README.md**: Updated with Vue usage prominently featured
+- **VueComponent.vue**: Real-world example component
+- Migration guide for existing users
+
+### 5. Backward Compatibility
+
+- Legacy API completely unchanged
+- Existing code continues to work without modifications
+- Tests prove no regressions
+- Package exports allow both APIs to coexist:
+  ```javascript
+  // Legacy
+  const _ = require('supergroup');
+  
+  // New
+  import { useGrouping } from 'supergroup/composables';
+  ```
+
+## Key Features of New API
+
+### Reactivity
+```javascript
+const data = ref([...]);
+const grouping = useGrouping(data, 'category');
+
+// Automatically updates when data changes!
+data.value.push(newItem);
+```
+
+### Modularity
+```javascript
+// Use only what you need
+import { useGrouping, useGroupSelection } from 'supergroup/composables';
+```
+
+### Type-Safe
+Designed with TypeScript support in mind (definitions can be added later)
+
+### Vue 3 Best Practices
+- Composition API patterns
+- Proper ref/computed usage
+- No direct mutations
+- Reactive state management
+
+## Files Changed
+
+### New Files
+- `src/composables/useGrouping.js` - Main grouping logic
+- `src/composables/useGroupList.js` - List operations
+- `src/composables/useGroupValue.js` - Value operations
+- `src/composables/useGroupSelection.js` - Selection state
+- `src/utils/groupHelpers.js` - Pure utility functions
+- `src/index.js` - Main exports
+- `test/composables.test.js` - New test suite
+- `examples/VueComponent.vue` - Example usage
+- `COMPOSABLES.md` - API documentation
+
+### Modified Files
+- `package.json` - Dual module exports, Vue peer dependency
+- `README.md` - Featured new API
+- `supergroup.js` → `supergroup.cjs` - Legacy API (renamed)
+- `test/supergroup_vows.js` → `test/supergroup_vows.cjs` - Legacy tests
+
+## Quality Metrics
+
+- **Code Coverage**: All major paths tested
+- **Security**: Zero vulnerabilities (CodeQL)
+- **Backward Compatibility**: 100% (30/30 legacy tests pass)
+- **New Features**: Fully tested (13/13 composable tests pass)
+- **Documentation**: Comprehensive with examples
+- **Best Practices**: Follows Vue 3 Composition API patterns
+
+## Usage Example
+
+```vue
+<template>
+  <div>
+    <div v-for="group in grouped.values" :key="group.value"
+         @click="selection.toggleValue(group)"
+         :class="{ selected: selection.isSelected(group) }">
+      {{ group.value }} ({{ group.records.length }} items)
+    </div>
+  </div>
+</template>
+
+<script setup>
+import { ref } from 'vue';
+import { useGrouping, useGroupSelection } from 'supergroup/composables';
+
+const data = ref([/* your data */]);
+const { grouped } = useGrouping(data, 'category');
+const selection = useGroupSelection(grouped);
+</script>
+```
+
+## Migration Path
+
+### For New Projects
+Use the Vue composables API from the start.
+
+### For Existing Projects
+Continue using the legacy API. Migrate to composables when:
+- Adding new Vue.js features
+- Needing reactive grouping
+- Wanting better modularity
+
+Both APIs will be maintained.
+
+## Future Enhancements (Not in Scope)
+
+Potential additions that could be made in future PRs:
+- TypeScript definitions (.d.ts files)
+- Additional composables for common patterns
+- Performance optimizations for large datasets
+- More D3.js integration helpers
+- React hooks version (separate package)
+
+## Conclusion
+
+This refactor successfully modernizes supergroup for Vue.js applications while respecting the existing user base. The library is now:
+
+- ✅ **Modern**: ES modules, Vue 3 composables
+- ✅ **Reactive**: Automatic updates with data changes
+- ✅ **Modular**: Import only what you need
+- ✅ **Backward Compatible**: Legacy API untouched
+- ✅ **Well Tested**: 43 total tests passing
+- ✅ **Documented**: Comprehensive guides and examples
+- ✅ **Secure**: No vulnerabilities
+
+The refactor provides a clear path forward for Vue.js developers while maintaining full support for existing users.
diff --git a/dist/composables/useGroupList.d.ts b/dist/composables/useGroupList.d.ts
new file mode 100644
index 0000000..d90d07c
--- /dev/null
+++ b/dist/composables/useGroupList.d.ts
@@ -0,0 +1,13 @@
+/**
+ * Composable for working with group lists
+ * Provides lookup, sorting, aggregation, and navigation
+ */
+import { type Ref, type ComputedRef } from 'vue';
+import type { GroupResult, UseGroupListReturn } from '../types';
+/**
+ * Group list composable
+ * @param groupResult - Result from useGrouping (can be a computed ref)
+ * @returns List operations and utilities
+ */
+export declare function useGroupList<T extends Record<string, any>>(groupResult: GroupResult<T> | Ref<GroupResult<T>> | ComputedRef<GroupResult<T>>): UseGroupListReturn<T>;
+//# sourceMappingURL=useGroupList.d.ts.map
\ No newline at end of file
diff --git a/dist/composables/useGroupList.d.ts.map b/dist/composables/useGroupList.d.ts.map
new file mode 100644
index 0000000..87b23fb
--- /dev/null
+++ b/dist/composables/useGroupList.d.ts.map
@@ -0,0 +1 @@
+{"version":3,"file":"useGroupList.d.ts","sourceRoot":"","sources":["../../src/composables/useGroupList.ts"],"names":[],"mappings":"AAAA;;;GAGG;AAEH,OAAO,EAAwB,KAAK,GAAG,EAAE,KAAK,WAAW,EAAE,MAAM,KAAK,CAAC;AAEvE,OAAO,KAAK,EACV,WAAW,EAKX,kBAAkB,EACnB,MAAM,UAAU,CAAC;AAElB;;;;GAIG;AACH,wBAAgB,YAAY,CAAC,CAAC,SAAS,MAAM,CAAC,MAAM,EAAE,GAAG,CAAC,EACxD,WAAW,EAAE,WAAW,CAAC,CAAC,CAAC,GAAG,GAAG,CAAC,WAAW,CAAC,CAAC,CAAC,CAAC,GAAG,WAAW,CAAC,WAAW,CAAC,CAAC,CAAC,CAAC,GAC9E,kBAAkB,CAAC,CAAC,CAAC,CAsTvB"}
\ No newline at end of file
diff --git a/dist/composables/useGroupList.js b/dist/composables/useGroupList.js
new file mode 100644
index 0000000..08a99da
--- /dev/null
+++ b/dist/composables/useGroupList.js
@@ -0,0 +1,279 @@
+/**
+ * Composable for working with group lists
+ * Provides lookup, sorting, aggregation, and navigation
+ */
+import { computed, ref, isRef } from 'vue';
+import _ from 'lodash';
+/**
+ * Group list composable
+ * @param groupResult - Result from useGrouping (can be a computed ref)
+ * @returns List operations and utilities
+ */
+export function useGroupList(groupResult) {
+    // Keep reactivity - if it's a ref, use it directly
+    const groupRef = isRef(groupResult) ? groupResult : ref(groupResult);
+    /**
+     * Get values array
+     */
+    const values = computed(() => {
+        const group = groupRef.value;
+        return (group.values || []);
+    });
+    /**
+     * Get child property name
+     */
+    const childProp = computed(() => {
+        const group = groupRef.value;
+        return group.childProp || 'children';
+    });
+    /**
+     * Lookup single value
+     */
+    const singleLookup = (query) => {
+        return values.value.find(v => v.value == query);
+    };
+    /**
+     * Lookup value or path
+     */
+    const lookup = (query) => {
+        if (Array.isArray(query)) {
+            // Path lookup for hierarchical groups
+            let result = singleLookup(query[0]);
+            for (let i = 1; i < query.length && result; i++) {
+                const children = result[childProp.value];
+                if (!children)
+                    break;
+                result = children.find(v => v.value == query[i]);
+            }
+            return result;
+        }
+        else {
+            // Single value lookup
+            return singleLookup(query);
+        }
+    };
+    /**
+     * Lookup multiple values
+     */
+    const lookupMany = (queries) => {
+        return queries
+            .map(q => singleLookup(q))
+            .filter((v) => v !== undefined);
+    };
+    /**
+     * Get raw values array
+     */
+    const rawValues = computed(() => {
+        return values.value.map(v => v.value);
+    });
+    /**
+     * Flatten entire tree into single array
+     */
+    const flattenTree = computed(() => {
+        const result = [];
+        const prop = childProp.value;
+        const flatten = (vals) => {
+            vals.forEach(val => {
+                result.push(val);
+                const children = val[prop];
+                if (children && children.length > 0) {
+                    flatten(children);
+                }
+            });
+        };
+        flatten(values.value);
+        return result;
+    });
+    /**
+     * Get all leaf nodes
+     */
+    const leafNodes = computed(() => {
+        const prop = childProp.value;
+        return flattenTree.value.filter(v => {
+            const children = v[prop];
+            return !children || children.length === 0;
+        });
+    });
+    /**
+     * Get nodes at specific level
+     */
+    const nodesAtLevel = (level) => {
+        if (level === 0)
+            return values.value;
+        const result = [];
+        const prop = childProp.value;
+        const traverse = (vals, currentLevel) => {
+            if (currentLevel === level) {
+                result.push(...vals);
+                return;
+            }
+            vals.forEach(v => {
+                const children = v[prop];
+                if (children && children.length > 0) {
+                    traverse(children, currentLevel + 1);
+                }
+            });
+        };
+        traverse(values.value, 0);
+        return result;
+    };
+    /**
+     * Get name paths for all values
+     */
+    const namePaths = (opts = {}) => {
+        const delim = opts.delim || '/';
+        return values.value.map(v => {
+            const path = [];
+            let ptr = v;
+            path.push(ptr.value);
+            while (ptr.parent) {
+                ptr = ptr.parent;
+                path.unshift(ptr.value);
+            }
+            if (opts.noRoot)
+                path.shift();
+            if (opts.backwards)
+                path.reverse();
+            return path.join(delim);
+        });
+    };
+    /**
+     * Apply aggregation to all values
+     */
+    const aggregates = (func, field, returnType = 'array') => {
+        const results = values.value.map(val => {
+            const fieldValues = field
+                ? (_.isFunction(field) ? _.map(val.records, field) : _.map(val.records, field))
+                : val.records;
+            return func(fieldValues);
+        });
+        if (returnType === 'dict') {
+            return _.zipObject(rawValues.value, results);
+        }
+        return results;
+    };
+    /**
+     * Sort values
+     */
+    const sort = (compareFn) => {
+        return [...values.value].sort(compareFn);
+    };
+    /**
+     * Sort values by function
+     */
+    const sortBy = (iteratee) => {
+        return _.sortBy(values.value, iteratee);
+    };
+    /**
+     * Convert to D3 nest entries format
+     */
+    const toD3Entries = () => {
+        const prop = childProp.value;
+        const convert = (vals) => {
+            return vals.map(val => {
+                const children = val[prop];
+                if (children && children.length > 0) {
+                    return {
+                        key: String(val.value),
+                        values: convert(children)
+                    };
+                }
+                return {
+                    key: String(val.value),
+                    values: val.records
+                };
+            });
+        };
+        return convert(values.value);
+    };
+    /**
+     * Convert to D3 nest map format
+     */
+    const toD3Map = () => {
+        const prop = childProp.value;
+        const convert = (vals) => {
+            const result = {};
+            vals.forEach(val => {
+                const key = String(val.value);
+                const children = val[prop];
+                if (children && children.length > 0) {
+                    result[key] = convert(children);
+                }
+                else {
+                    result[key] = [...val.records];
+                }
+            });
+            return result;
+        };
+        return convert(values.value);
+    };
+    /**
+     * Create root value wrapper
+     */
+    const asRootVal = (name = 'Root', dimName = 'root') => {
+        const prop = childProp.value;
+        const group = groupRef.value;
+        const rootVal = {
+            value: name,
+            rawValue: name,
+            dim: dimName,
+            depth: 0,
+            records: group.records,
+            parent: null,
+            [prop]: values.value
+        };
+        // Update children to reference new root
+        values.value.forEach(v => {
+            v.parent = rootVal;
+            // Update all descendant depths
+            const updateDepth = (val, increment) => {
+                val.depth += increment;
+                const children = val[prop];
+                if (children) {
+                    children.forEach(child => updateDepth(child, increment));
+                }
+            };
+            updateDepth(v, 1);
+        });
+        return rootVal;
+    };
+    /**
+     * Get summary string for debugging
+     */
+    const summary = (depth = 0) => {
+        const group = groupRef.value;
+        const prop = childProp.value;
+        const indent = '    '.repeat(depth);
+        const dim = group.dim || 'unknown';
+        const vals = values.value.length;
+        const recs = group.records ? group.records.length : 0;
+        const lines = [`${indent}${String(dim)}, ${recs} recs (${depth}) ${vals} vals:`];
+        values.value.forEach(val => {
+            const valRecs = val.records ? val.records.length : 0;
+            const valIndent = '    '.repeat(depth + 1);
+            lines.push(`${valIndent}${val.value}, ${valRecs} recs`);
+            const children = val[prop];
+            if (children && children.length > 0) {
+                lines.push(`${valIndent}has ${children.length} children`);
+            }
+        });
+        return lines.join('\n');
+    };
+    return {
+        values,
+        lookup,
+        lookupMany,
+        rawValues,
+        flattenTree,
+        leafNodes,
+        nodesAtLevel,
+        namePaths,
+        aggregates,
+        sort,
+        sortBy,
+        toD3Entries,
+        toD3Map,
+        asRootVal,
+        summary
+    };
+}
diff --git a/dist/composables/useGroupSelection.d.ts b/dist/composables/useGroupSelection.d.ts
new file mode 100644
index 0000000..d512cf2
--- /dev/null
+++ b/dist/composables/useGroupSelection.d.ts
@@ -0,0 +1,13 @@
+/**
+ * Composable for managing selection state on groups
+ * Provides reactive selection without mutating the original data
+ */
+import { type Ref, type ComputedRef } from 'vue';
+import type { GroupResult, UseGroupSelectionReturn } from '../types';
+/**
+ * Group selection composable
+ * @param groupResult - Result from useGrouping
+ * @returns Selection state and methods
+ */
+export declare function useGroupSelection<T extends Record<string, any>>(groupResult: GroupResult<T> | Ref<GroupResult<T>> | ComputedRef<GroupResult<T>>): UseGroupSelectionReturn<T>;
+//# sourceMappingURL=useGroupSelection.d.ts.map
\ No newline at end of file
diff --git a/dist/composables/useGroupSelection.d.ts.map b/dist/composables/useGroupSelection.d.ts.map
new file mode 100644
index 0000000..e002c94
--- /dev/null
+++ b/dist/composables/useGroupSelection.d.ts.map
@@ -0,0 +1 @@
+{"version":3,"file":"useGroupSelection.d.ts","sourceRoot":"","sources":["../../src/composables/useGroupSelection.ts"],"names":[],"mappings":"AAAA;;;GAGG;AAEH,OAAO,EAAwB,KAAK,GAAG,EAAE,KAAK,WAAW,EAAE,MAAM,KAAK,CAAC;AAEvE,OAAO,KAAK,EAAE,WAAW,EAAc,uBAAuB,EAAoB,MAAM,UAAU,CAAC;AAEnG;;;;GAIG;AACH,wBAAgB,iBAAiB,CAAC,CAAC,SAAS,MAAM,CAAC,MAAM,EAAE,GAAG,CAAC,EAC7D,WAAW,EAAE,WAAW,CAAC,CAAC,CAAC,GAAG,GAAG,CAAC,WAAW,CAAC,CAAC,CAAC,CAAC,GAAG,WAAW,CAAC,WAAW,CAAC,CAAC,CAAC,CAAC,GAC9E,uBAAuB,CAAC,CAAC,CAAC,CAkN5B"}
\ No newline at end of file
diff --git a/dist/composables/useGroupSelection.js b/dist/composables/useGroupSelection.js
new file mode 100644
index 0000000..ba511f4
--- /dev/null
+++ b/dist/composables/useGroupSelection.js
@@ -0,0 +1,196 @@
+/**
+ * Composable for managing selection state on groups
+ * Provides reactive selection without mutating the original data
+ */
+import { ref, computed, isRef } from 'vue';
+import _ from 'lodash';
+/**
+ * Group selection composable
+ * @param groupResult - Result from useGrouping
+ * @returns Selection state and methods
+ */
+export function useGroupSelection(groupResult) {
+    const groupRef = isRef(groupResult) ? groupResult : ref(groupResult);
+    // Track selected values - use any to avoid Vue's unwrap issues
+    const selectedValues = ref([]);
+    // Track highlighted values (for hover, etc.)
+    const highlightedValues = ref([]);
+    /**
+     * Select a value
+     */
+    const selectValue = (value) => {
+        if (!selectedValues.value.includes(value)) {
+            selectedValues.value.push(value);
+        }
+    };
+    /**
+     * Deselect a value
+     */
+    const deselectValue = (value) => {
+        const index = selectedValues.value.indexOf(value);
+        if (index > -1) {
+            selectedValues.value.splice(index, 1);
+        }
+    };
+    /**
+     * Toggle value selection
+     */
+    const toggleValue = (value) => {
+        if (selectedValues.value.includes(value)) {
+            deselectValue(value);
+        }
+        else {
+            selectValue(value);
+        }
+    };
+    /**
+     * Clear all selections
+     */
+    const clearSelection = () => {
+        selectedValues.value = [];
+    };
+    /**
+     * Select multiple values
+     */
+    const selectMany = (values) => {
+        values.forEach(v => selectValue(v));
+    };
+    /**
+     * Check if value is selected
+     */
+    const isSelected = (value) => {
+        return selectedValues.value.includes(value);
+    };
+    /**
+     * Get all records from selected values
+     */
+    const selectedRecords = computed(() => {
+        return _.chain(selectedValues.value)
+            .map('records')
+            .flatten()
+            .value();
+    });
+    /**
+     * Get count of selected values
+     */
+    const selectedCount = computed(() => {
+        return selectedValues.value.length;
+    });
+    /**
+     * Highlight a value (for hover effects, etc.)
+     */
+    const highlightValue = (value) => {
+        if (!highlightedValues.value.includes(value)) {
+            highlightedValues.value.push(value);
+        }
+    };
+    /**
+     * Remove highlight from value
+     */
+    const unhighlightValue = (value) => {
+        const index = highlightedValues.value.indexOf(value);
+        if (index > -1) {
+            highlightedValues.value.splice(index, 1);
+        }
+    };
+    /**
+     * Clear all highlights
+     */
+    const clearHighlights = () => {
+        highlightedValues.value = [];
+    };
+    /**
+     * Check if value is highlighted
+     */
+    const isHighlighted = (value) => {
+        return highlightedValues.value.includes(value);
+    };
+    /**
+     * Select by filter function
+     */
+    const selectByFilter = (filterFn) => {
+        const group = groupRef.value;
+        if (!group)
+            return;
+        const values = group.values || [];
+        // Flatten tree and filter
+        const flatValues = [];
+        const flatten = (vals) => {
+            vals.forEach((v) => {
+                flatValues.push(v);
+                const childProp = group.childProp || 'children';
+                const children = v[childProp];
+                if (children) {
+                    flatten(children);
+                }
+            });
+        };
+        flatten(values);
+        const matching = flatValues.filter(filterFn);
+        selectMany(matching);
+    };
+    /**
+     * Select all leaf nodes
+     */
+    const selectLeafNodes = () => {
+        const group = groupRef.value;
+        if (!group)
+            return;
+        const childProp = group.childProp || 'children';
+        const leaves = [];
+        const findLeaves = (vals) => {
+            vals.forEach((v) => {
+                const children = v[childProp];
+                if (!children || children.length === 0) {
+                    leaves.push(v);
+                }
+                else {
+                    findLeaves(children);
+                }
+            });
+        };
+        findLeaves(group.values || []);
+        selectMany(leaves);
+    };
+    /**
+     * Select values at specific depth
+     */
+    const selectAtDepth = (depth) => {
+        selectByFilter(v => v.depth === depth);
+    };
+    /**
+     * Get selection state summary
+     */
+    const selectionSummary = computed(() => {
+        return {
+            count: selectedCount.value,
+            recordCount: selectedRecords.value.length,
+            values: selectedValues.value.map((v) => v.value)
+        };
+    });
+    return {
+        // State
+        selectedValues: selectedValues,
+        highlightedValues: highlightedValues,
+        // Selection methods
+        selectValue,
+        deselectValue,
+        toggleValue,
+        clearSelection,
+        selectMany,
+        isSelected,
+        // Computed
+        selectedRecords,
+        selectedCount,
+        selectionSummary,
+        // Highlight methods
+        highlightValue,
+        unhighlightValue,
+        clearHighlights,
+        isHighlighted,
+        // Advanced selection
+        selectByFilter,
+        selectLeafNodes,
+        selectAtDepth
+    };
+}
diff --git a/dist/composables/useGroupValue.d.ts b/dist/composables/useGroupValue.d.ts
new file mode 100644
index 0000000..fa2443f
--- /dev/null
+++ b/dist/composables/useGroupValue.d.ts
@@ -0,0 +1,13 @@
+/**
+ * Composable for working with individual group values
+ * Provides methods for paths, aggregates, and navigation
+ */
+import type { GroupValue, UseGroupValueReturn } from '../types';
+/**
+ * Group value composable
+ * @param value - Group value object
+ * @param childProp - Property name for children (default: 'children')
+ * @returns Methods and computed properties for the value
+ */
+export declare function useGroupValue<T extends Record<string, any>>(value: GroupValue<T>, childProp?: string): UseGroupValueReturn<T>;
+//# sourceMappingURL=useGroupValue.d.ts.map
\ No newline at end of file
diff --git a/dist/composables/useGroupValue.d.ts.map b/dist/composables/useGroupValue.d.ts.map
new file mode 100644
index 0000000..39b085d
--- /dev/null
+++ b/dist/composables/useGroupValue.d.ts.map
@@ -0,0 +1 @@
+{"version":3,"file":"useGroupValue.d.ts","sourceRoot":"","sources":["../../src/composables/useGroupValue.ts"],"names":[],"mappings":"AAAA;;;GAGG;AAKH,OAAO,KAAK,EAAE,UAAU,EAAe,mBAAmB,EAAE,MAAM,UAAU,CAAC;AAE7E;;;;;GAKG;AACH,wBAAgB,aAAa,CAAC,CAAC,SAAS,MAAM,CAAC,MAAM,EAAE,GAAG,CAAC,EACzD,KAAK,EAAE,UAAU,CAAC,CAAC,CAAC,EACpB,SAAS,GAAE,MAAmB,GAC7B,mBAAmB,CAAC,CAAC,CAAC,CAiMxB"}
\ No newline at end of file
diff --git a/dist/composables/useGroupValue.js b/dist/composables/useGroupValue.js
new file mode 100644
index 0000000..b636a04
--- /dev/null
+++ b/dist/composables/useGroupValue.js
@@ -0,0 +1,188 @@
+/**
+ * Composable for working with individual group values
+ * Provides methods for paths, aggregates, and navigation
+ */
+import { computed } from 'vue';
+import { createAggregator, calculatePct } from '../utils/groupHelpers';
+/**
+ * Group value composable
+ * @param value - Group value object
+ * @param childProp - Property name for children (default: 'children')
+ * @returns Methods and computed properties for the value
+ */
+export function useGroupValue(value, childProp = 'children') {
+    const val = value;
+    /**
+     * Get value's children
+     */
+    const children = computed(() => {
+        return val[childProp] || [];
+    });
+    /**
+     * Check if value has children
+     */
+    const hasChildren = computed(() => {
+        return children.value && children.value.length > 0;
+    });
+    /**
+     * Get all descendants (recursive)
+     */
+    const descendants = computed(() => {
+        if (!hasChildren.value)
+            return [];
+        const result = [];
+        const traverse = (vals) => {
+            vals.forEach(v => {
+                result.push(v);
+                const kids = v[childProp];
+                if (kids && kids.length > 0) {
+                    traverse(kids);
+                }
+            });
+        };
+        traverse(children.value);
+        return result;
+    });
+    /**
+     * Get leaf nodes (values with no children)
+     */
+    const leafNodes = computed(() => {
+        if (!hasChildren.value)
+            return [val];
+        return descendants.value.filter(v => {
+            const kids = v[childProp];
+            return !kids || kids.length === 0;
+        });
+    });
+    /**
+     * Get path from root to this value
+     */
+    const pedigree = computed(() => {
+        const path = [];
+        let ptr = val;
+        path.push(ptr);
+        while (ptr.parent) {
+            ptr = ptr.parent;
+            path.unshift(ptr);
+        }
+        return path;
+    });
+    /**
+     * Get name path (string representation)
+     */
+    const namePath = (opts = {}) => {
+        const delim = opts.delim || '/';
+        const path = pedigree.value.map(v => v.value);
+        if (opts.noRoot)
+            path.shift();
+        if (opts.backwards)
+            path.reverse();
+        return opts.asArray ? path : path.join(delim);
+    };
+    /**
+     * Get dimension path
+     */
+    const dimPath = (opts = {}) => {
+        const delim = opts.delim || '/';
+        const path = pedigree.value.map(v => String(v.dim));
+        if (opts.noRoot)
+            path.shift();
+        if (opts.backwards)
+            path.reverse();
+        return opts.asArray ? path : path.join(delim);
+    };
+    /**
+     * Calculate aggregate on records
+     */
+    const aggregate = (func, field) => {
+        return createAggregator(val.records, func, field);
+    };
+    /**
+     * Get percentage of parent
+     */
+    const pct = computed(() => {
+        if (!val.parent || !val.parent.records)
+            return 1;
+        return calculatePct(val.records, val.parent.records);
+    });
+    /**
+     * Get previous sibling
+     */
+    const previous = () => {
+        if (!val.parent)
+            return null;
+        const siblings = val.parent[childProp];
+        if (!siblings)
+            return null;
+        const index = siblings.indexOf(val);
+        return index > 0 ? siblings[index - 1] : null;
+    };
+    /**
+     * Get next sibling
+     */
+    const next = () => {
+        if (!val.parent)
+            return null;
+        const siblings = val.parent[childProp];
+        if (!siblings)
+            return null;
+        const index = siblings.indexOf(val);
+        return index < siblings.length - 1 ? siblings[index + 1] : null;
+    };
+    /**
+     * Lookup child by value or path
+     */
+    const lookup = (query) => {
+        if (!hasChildren.value) {
+            throw new Error("Cannot lookup on value without children");
+        }
+        if (Array.isArray(query)) {
+            // Path lookup
+            if (val.value == query[0]) {
+                const newQuery = query.slice(1);
+                if (newQuery.length === 0)
+                    return val;
+                query = newQuery;
+            }
+            const queryArray = query;
+            let result = children.value.find(c => c.value == queryArray[0]);
+            for (let i = 1; i < queryArray.length && result; i++) {
+                const childVals = result[childProp];
+                if (!childVals)
+                    break;
+                result = childVals.find(c => c.value == queryArray[i]);
+            }
+            return result;
+        }
+        else {
+            // Single value lookup
+            return children.value.find(c => c.value == query);
+        }
+    };
+    /**
+     * Get root value
+     */
+    const rootValue = computed(() => {
+        let ptr = val;
+        while (ptr.parent) {
+            ptr = ptr.parent;
+        }
+        return ptr;
+    });
+    return {
+        value: val,
+        children,
+        hasChildren,
+        descendants,
+        leafNodes,
+        pedigree,
+        namePath,
+        dimPath,
+        aggregate,
+        pct,
+        previous,
+        next,
+        lookup,
+        rootValue
+    };
+}
diff --git a/dist/composables/useGrouping.d.ts b/dist/composables/useGrouping.d.ts
new file mode 100644
index 0000000..fbc5c20
--- /dev/null
+++ b/dist/composables/useGrouping.d.ts
@@ -0,0 +1,15 @@
+/**
+ * Core grouping composable for Vue.js applications
+ * Provides reactive grouping functionality
+ */
+import { type Ref } from 'vue';
+import type { GroupingOptions, Dimension, UseGroupingReturn } from '../types';
+/**
+ * Main grouping composable
+ * @param records - Records to group (can be reactive)
+ * @param dimensions - Single dimension or array for multi-level
+ * @param options - Grouping options
+ * @returns Reactive grouping result with helper methods
+ */
+export declare function useGrouping<T extends Record<string, any>>(records: T[] | Ref<T[]>, dimensions: Dimension<T> | Ref<Dimension<T>>, options?: GroupingOptions | Ref<GroupingOptions>): UseGroupingReturn<T>;
+//# sourceMappingURL=useGrouping.d.ts.map
\ No newline at end of file
diff --git a/dist/composables/useGrouping.d.ts.map b/dist/composables/useGrouping.d.ts.map
new file mode 100644
index 0000000..7f935c1
--- /dev/null
+++ b/dist/composables/useGrouping.d.ts.map
@@ -0,0 +1 @@
+{"version":3,"file":"useGrouping.d.ts","sourceRoot":"","sources":["../../src/composables/useGrouping.ts"],"names":[],"mappings":"AAAA;;;GAGG;AAEH,OAAO,EAAwB,KAAK,GAAG,EAAoB,MAAM,KAAK,CAAC;AAOvE,OAAO,KAAK,EACV,eAAe,EAGf,SAAS,EACT,iBAAiB,EAClB,MAAM,UAAU,CAAC;AAElB;;;;;;GAMG;AACH,wBAAgB,WAAW,CAAC,CAAC,SAAS,MAAM,CAAC,MAAM,EAAE,GAAG,CAAC,EACvD,OAAO,EAAE,CAAC,EAAE,GAAG,GAAG,CAAC,CAAC,EAAE,CAAC,EACvB,UAAU,EAAE,SAAS,CAAC,CAAC,CAAC,GAAG,GAAG,CAAC,SAAS,CAAC,CAAC,CAAC,CAAC,EAC5C,OAAO,GAAE,eAAe,GAAG,GAAG,CAAC,eAAe,CAAM,GACnD,iBAAiB,CAAC,CAAC,CAAC,CAiOtB"}
\ No newline at end of file
diff --git a/dist/composables/useGrouping.js b/dist/composables/useGrouping.js
new file mode 100644
index 0000000..0bde859
--- /dev/null
+++ b/dist/composables/useGrouping.js
@@ -0,0 +1,199 @@
+/**
+ * Core grouping composable for Vue.js applications
+ * Provides reactive grouping functionality
+ */
+import { ref, computed, isRef } from 'vue';
+import _ from 'lodash';
+import { isNumericGroup, filterOutEmpty, multiValuedGroupBy } from '../utils/groupHelpers';
+/**
+ * Main grouping composable
+ * @param records - Records to group (can be reactive)
+ * @param dimensions - Single dimension or array for multi-level
+ * @param options - Grouping options
+ * @returns Reactive grouping result with helper methods
+ */
+export function useGrouping(records, dimensions, options = {}) {
+    // Keep reactivity by checking if already a ref
+    const recordsRef = isRef(records) ? records : ref(records);
+    const dimensionsRef = isRef(dimensions) ? dimensions : ref(dimensions);
+    const optionsRef = isRef(options) ? options : ref(options);
+    /**
+     * Core grouping logic for single dimension
+     */
+    const groupByDimension = (recs, dim, opts) => {
+        const childProp = opts.childProp || 'children';
+        // Clone records with index tracking
+        const clonedRecs = recs.map((rec, i) => ({
+            ...rec,
+            _recIdx: i
+        }));
+        // Apply pre-processing hook if provided
+        const processedRecs = opts.preListRecsHook ?
+            opts.preListRecsHook(clonedRecs) : clonedRecs;
+        // Perform grouping
+        let groups;
+        if (opts.multiValuedGroup) {
+            const dimFunc = typeof dim === 'function' ? dim : (d) => d[dim];
+            const arrayDim = (val) => {
+                const retVal = dimFunc(val);
+                return Array.isArray(retVal) ? retVal : [retVal];
+            };
+            groups = multiValuedGroupBy(processedRecs, arrayDim);
+        }
+        else {
+            if (opts.truncateBranchOnEmptyVal) {
+                const filtered = filterOutEmpty(processedRecs, dim);
+                groups = _.groupBy(filtered, dim);
+            }
+            else {
+                groups = _.groupBy(processedRecs, dim);
+            }
+        }
+        // Exclude specific values if specified
+        if (opts.excludeValues) {
+            opts.excludeValues.forEach(val => {
+                delete groups[String(val)];
+            });
+        }
+        // Determine if group is numeric
+        const isNumeric = _.has(opts, 'isNumeric') ?
+            opts.isNumeric : isNumericGroup(groups);
+        // Create group values
+        const groupValues = _.map(_.toPairs(groups), ([key, groupRecs]) => {
+            const value = {
+                value: isNumeric ? Number(key) : String(key),
+                rawValue: key,
+                records: groupRecs,
+                dim: opts.dimName || dim,
+                depth: opts.parent ? (opts.parent.depth + 1) : 0,
+                parent: opts.parent || null,
+                [childProp]: null
+            };
+            return value;
+        });
+        // Create list metadata
+        const result = {
+            values: groupValues,
+            records: clonedRecs,
+            dim: opts.dimName || dim,
+            isNumeric,
+            childProp
+        };
+        return result;
+    };
+    /**
+     * Multi-level grouping
+     */
+    const groupByMultipleDimensions = (recs, dims, opts) => {
+        let currentGroup = groupByDimension(recs, dims[0], opts);
+        // Add subsequent levels
+        for (let i = 1; i < dims.length; i++) {
+            const dim = dims[i];
+            currentGroup.values.forEach(val => {
+                const childGroup = groupByDimension(val.records, dim, { ...opts, parent: val });
+                val[currentGroup.childProp] = childGroup.values;
+            });
+        }
+        return currentGroup;
+    };
+    /**
+     * Computed grouped result
+     */
+    const grouped = computed(() => {
+        const recs = recordsRef.value;
+        const dims = dimensionsRef.value;
+        const opts = optionsRef.value;
+        if (!recs || recs.length === 0) {
+            return {
+                values: [],
+                records: [],
+                dim: null,
+                isNumeric: false,
+                childProp: opts.childProp || 'children'
+            };
+        }
+        if (Array.isArray(dims)) {
+            return groupByMultipleDimensions(recs, dims, opts);
+        }
+        else {
+            return groupByDimension(recs, dims, opts);
+        }
+    });
+    /**
+     * Helper methods
+     */
+    const methods = {
+        // Get all values as plain array
+        rawValues: computed(() => grouped.value.values.map(v => v.value)),
+        // Get all records
+        allRecords: computed(() => grouped.value.records),
+        // Lookup a value
+        lookup: (query) => {
+            const values = grouped.value.values;
+            if (Array.isArray(query)) {
+                // Path lookup for hierarchical groups
+                let result = values.find(v => v.value == query[0]);
+                for (let i = 1; i < query.length && result; i++) {
+                    const children = result[grouped.value.childProp];
+                    if (!children)
+                        break;
+                    result = children.find(v => v.value == query[i]);
+                }
+                return result;
+            }
+            else {
+                // Single value lookup
+                return values.find(v => v.value == query);
+            }
+        },
+        // Add another level of grouping
+        addLevel: (newDim, newOpts = {}) => {
+            const current = grouped.value;
+            const childProp = current.childProp;
+            current.values.forEach(val => {
+                if (!val[childProp]) {
+                    const childGroup = groupByDimension(val.records, newDim, { ...newOpts, parent: val });
+                    val[childProp] = childGroup.values;
+                }
+            });
+        },
+        // Get leaf nodes
+        leafNodes: computed(() => {
+            const childProp = grouped.value.childProp;
+            const leaves = [];
+            const findLeaves = (values) => {
+                values.forEach(val => {
+                    const children = val[childProp];
+                    if (!children || children.length === 0) {
+                        leaves.push(val);
+                    }
+                    else {
+                        findLeaves(children);
+                    }
+                });
+            };
+            findLeaves(grouped.value.values);
+            return leaves;
+        }),
+        // Flatten entire tree
+        flattenTree: computed(() => {
+            const childProp = grouped.value.childProp;
+            const flat = [];
+            const flatten = (values) => {
+                values.forEach(val => {
+                    flat.push(val);
+                    const children = val[childProp];
+                    if (children && children.length > 0) {
+                        flatten(children);
+                    }
+                });
+            };
+            flatten(grouped.value.values);
+            return flat;
+        })
+    };
+    return {
+        grouped,
+        ...methods
+    };
+}
diff --git a/dist/index.d.ts b/dist/index.d.ts
new file mode 100644
index 0000000..f38f2ea
--- /dev/null
+++ b/dist/index.d.ts
@@ -0,0 +1,27 @@
+/**
+ * Supergroup Vue Composables
+ *
+ * A modular, reactive grouping utility for Vue.js applications
+ *
+ * @example
+ * import { ref } from 'vue';
+ * import { useGrouping, useGroupList } from 'supergroup/composables';
+ *
+ * const data = ref<MyRecord[]>([...]);
+ * const grouping = useGrouping(data, ['category', 'subcategory']);
+ * const list = useGroupList(grouping.grouped);
+ */
+import { useGrouping } from './composables/useGrouping';
+import { useGroupValue } from './composables/useGroupValue';
+import { useGroupList } from './composables/useGroupList';
+import { useGroupSelection } from './composables/useGroupSelection';
+import { isNumericGroup, filterOutEmpty, createDimPath, createAggregator, calculatePct, multiValuedGroupBy, findRootNodes } from './utils/groupHelpers';
+export { useGrouping, useGroupValue, useGroupList, useGroupSelection };
+export { isNumericGroup, filterOutEmpty, createDimPath, createAggregator, calculatePct, multiValuedGroupBy, findRootNodes };
+export type { PathOptions, GroupingOptions, Dimension, GroupValue, GroupResult, UseGroupingReturn, UseGroupValueReturn, UseGroupListReturn, UseGroupSelectionReturn, D3NestEntry, D3NestMap, SelectionSummary } from './types';
+/**
+ * Convenience function for quick grouping without Vue composable
+ * Useful for non-reactive contexts or server-side use
+ */
+export declare function supergroup<T extends Record<string, any>>(records: T[], dimensions: import('./types').Dimension<T>, options?: import('./types').GroupingOptions): import('./types').GroupResult<T>;
+//# sourceMappingURL=index.d.ts.map
\ No newline at end of file
diff --git a/dist/index.d.ts.map b/dist/index.d.ts.map
new file mode 100644
index 0000000..87903a0
--- /dev/null
+++ b/dist/index.d.ts.map
@@ -0,0 +1 @@
+{"version":3,"file":"index.d.ts","sourceRoot":"","sources":["../src/index.ts"],"names":[],"mappings":"AAAA;;;;;;;;;;;;GAYG;AAEH,OAAO,EAAE,WAAW,EAAE,MAAM,2BAA2B,CAAC;AACxD,OAAO,EAAE,aAAa,EAAE,MAAM,6BAA6B,CAAC;AAC5D,OAAO,EAAE,YAAY,EAAE,MAAM,4BAA4B,CAAC;AAC1D,OAAO,EAAE,iBAAiB,EAAE,MAAM,iCAAiC,CAAC;AAEpE,OAAO,EACL,cAAc,EACd,cAAc,EACd,aAAa,EACb,gBAAgB,EAChB,YAAY,EACZ,kBAAkB,EAClB,aAAa,EACd,MAAM,sBAAsB,CAAC;AAG9B,OAAO,EACL,WAAW,EACX,aAAa,EACb,YAAY,EACZ,iBAAiB,EAClB,CAAC;AAGF,OAAO,EACL,cAAc,EACd,cAAc,EACd,aAAa,EACb,gBAAgB,EAChB,YAAY,EACZ,kBAAkB,EAClB,aAAa,EACd,CAAC;AAGF,YAAY,EACV,WAAW,EACX,eAAe,EACf,SAAS,EACT,UAAU,EACV,WAAW,EACX,iBAAiB,EACjB,mBAAmB,EACnB,kBAAkB,EAClB,uBAAuB,EACvB,WAAW,EACX,SAAS,EACT,gBAAgB,EACjB,MAAM,SAAS,CAAC;AAEjB;;;GAGG;AACH,wBAAgB,UAAU,CAAC,CAAC,SAAS,MAAM,CAAC,MAAM,EAAE,GAAG,CAAC,EACtD,OAAO,EAAE,CAAC,EAAE,EACZ,UAAU,EAAE,OAAO,SAAS,EAAE,SAAS,CAAC,CAAC,CAAC,EAC1C,OAAO,GAAE,OAAO,SAAS,EAAE,eAAoB,GAC9C,OAAO,SAAS,EAAE,WAAW,CAAC,CAAC,CAAC,CAYlC"}
\ No newline at end of file
diff --git a/dist/index.js b/dist/index.js
new file mode 100644
index 0000000..d43d0da
--- /dev/null
+++ b/dist/index.js
@@ -0,0 +1,37 @@
+/**
+ * Supergroup Vue Composables
+ *
+ * A modular, reactive grouping utility for Vue.js applications
+ *
+ * @example
+ * import { ref } from 'vue';
+ * import { useGrouping, useGroupList } from 'supergroup/composables';
+ *
+ * const data = ref<MyRecord[]>([...]);
+ * const grouping = useGrouping(data, ['category', 'subcategory']);
+ * const list = useGroupList(grouping.grouped);
+ */
+import { useGrouping } from './composables/useGrouping';
+import { useGroupValue } from './composables/useGroupValue';
+import { useGroupList } from './composables/useGroupList';
+import { useGroupSelection } from './composables/useGroupSelection';
+import { isNumericGroup, filterOutEmpty, createDimPath, createAggregator, calculatePct, multiValuedGroupBy, findRootNodes } from './utils/groupHelpers';
+// Export all composables
+export { useGrouping, useGroupValue, useGroupList, useGroupSelection };
+// Export utility functions
+export { isNumericGroup, filterOutEmpty, createDimPath, createAggregator, calculatePct, multiValuedGroupBy, findRootNodes };
+/**
+ * Convenience function for quick grouping without Vue composable
+ * Useful for non-reactive contexts or server-side use
+ */
+export function supergroup(records, dimensions, options = {}) {
+    // Non-reactive version - just returns the grouped data
+    // Create a temporary ref-like wrapper
+    const recordsRef = { value: records };
+    const dimensionsRef = { value: dimensions };
+    const optionsRef = { value: options };
+    // Use the grouping composable
+    const grouping = useGrouping(recordsRef, dimensionsRef, optionsRef);
+    // Return just the grouped value, not reactive
+    return grouping.grouped.value;
+}
diff --git a/dist/types.d.ts b/dist/types.d.ts
new file mode 100644
index 0000000..b3886c5
--- /dev/null
+++ b/dist/types.d.ts
@@ -0,0 +1,150 @@
+/**
+ * Core type definitions for supergroup
+ */
+import { Ref, ComputedRef } from 'vue';
+/**
+ * Options for path formatting
+ */
+export interface PathOptions {
+    delim?: string;
+    dimName?: boolean;
+    noRoot?: boolean;
+    backwards?: boolean;
+    asArray?: boolean;
+}
+/**
+ * Options for grouping
+ */
+export interface GroupingOptions {
+    childProp?: string;
+    excludeValues?: (string | number)[];
+    dimName?: string;
+    truncateBranchOnEmptyVal?: boolean;
+    multiValuedGroup?: boolean;
+    preListRecsHook?: <T>(records: T[]) => T[];
+    isNumeric?: boolean;
+    parent?: GroupValue<any>;
+}
+/**
+ * Dimension type - can be a property key, function, or array of dimensions
+ */
+export type Dimension<T> = keyof T | ((record: T) => string | number) | Array<keyof T | ((record: T) => string | number)>;
+/**
+ * A group value with records and metadata
+ */
+export interface GroupValue<T> {
+    value: string | number;
+    rawValue: string;
+    records: T[];
+    dim: string | Dimension<T>;
+    depth: number;
+    parent: GroupValue<T> | null;
+    children?: GroupValue<T>[];
+    [key: string]: any;
+}
+/**
+ * Result of grouping operation
+ */
+export interface GroupResult<T> {
+    values: GroupValue<T>[];
+    records: T[];
+    dim: string | Dimension<T>;
+    isNumeric: boolean;
+    childProp: string;
+}
+/**
+ * Return type from useGrouping composable
+ */
+export interface UseGroupingReturn<T> {
+    grouped: ComputedRef<GroupResult<T>>;
+    rawValues: ComputedRef<(string | number)[]>;
+    allRecords: ComputedRef<T[]>;
+    lookup: (query: string | number | (string | number)[]) => GroupValue<T> | undefined;
+    addLevel: (newDim: Dimension<T>, newOpts?: GroupingOptions) => void;
+    leafNodes: ComputedRef<GroupValue<T>[]>;
+    flattenTree: ComputedRef<GroupValue<T>[]>;
+}
+/**
+ * Return type from useGroupValue composable
+ */
+export interface UseGroupValueReturn<T> {
+    value: GroupValue<T>;
+    children: ComputedRef<GroupValue<T>[]>;
+    hasChildren: ComputedRef<boolean>;
+    descendants: ComputedRef<GroupValue<T>[]>;
+    leafNodes: ComputedRef<GroupValue<T>[]>;
+    pedigree: ComputedRef<GroupValue<T>[]>;
+    namePath: (opts?: PathOptions) => string | (string | number)[];
+    dimPath: (opts?: PathOptions) => string | string[];
+    aggregate: <R>(func: (values: any[]) => R, field?: keyof T | ((record: T) => any)) => R;
+    pct: ComputedRef<number>;
+    previous: () => GroupValue<T> | null;
+    next: () => GroupValue<T> | null;
+    lookup: (query: string | number | (string | number)[]) => GroupValue<T> | undefined;
+    rootValue: ComputedRef<GroupValue<T>>;
+}
+/**
+ * D3 nest entry format
+ */
+export interface D3NestEntry<T> {
+    key: string;
+    values: D3NestEntry<T>[] | T[];
+}
+/**
+ * D3 nest map format
+ */
+export type D3NestMap<T> = {
+    [key: string]: D3NestMap<T> | T[];
+};
+/**
+ * Return type from useGroupList composable
+ */
+export interface UseGroupListReturn<T> {
+    values: ComputedRef<GroupValue<T>[]>;
+    lookup: (query: string | number | (string | number)[]) => GroupValue<T> | undefined;
+    lookupMany: (queries: (string | number)[]) => GroupValue<T>[];
+    rawValues: ComputedRef<(string | number)[]>;
+    flattenTree: ComputedRef<GroupValue<T>[]>;
+    leafNodes: ComputedRef<GroupValue<T>[]>;
+    nodesAtLevel: (level: number) => GroupValue<T>[];
+    namePaths: (opts?: PathOptions) => string[];
+    aggregates: <R>(func: (values: any[]) => R, field?: keyof T | ((record: T) => any), returnType?: 'array' | 'dict') => R[] | Record<string | number, R>;
+    sort: (compareFn: (a: GroupValue<T>, b: GroupValue<T>) => number) => GroupValue<T>[];
+    sortBy: (iteratee: ((value: GroupValue<T>) => any) | keyof GroupValue<T>) => GroupValue<T>[];
+    toD3Entries: () => D3NestEntry<T>[];
+    toD3Map: () => D3NestMap<T>;
+    asRootVal: (name?: string, dimName?: string) => GroupValue<T>;
+    summary: (depth?: number) => string;
+}
+/**
+ * Selection summary
+ */
+export interface SelectionSummary {
+    count: number;
+    recordCount: number;
+    values: (string | number)[];
+}
+/**
+ * Return type from useGroupSelection composable
+ */
+export interface UseGroupSelectionReturn<T> {
+    selectedValues: Ref<GroupValue<T>[]>;
+    highlightedValues: Ref<GroupValue<T>[]>;
+    selectValue: (value: GroupValue<T>) => void;
+    deselectValue: (value: GroupValue<T>) => void;
+    toggleValue: (value: GroupValue<T>) => void;
+    clearSelection: () => void;
+    selectMany: (values: GroupValue<T>[]) => void;
+    isSelected: (value: GroupValue<T>) => boolean;
+    selectedRecords: ComputedRef<T[]>;
+    selectedCount: ComputedRef<number>;
+    selectionSummary: ComputedRef<SelectionSummary>;
+    highlightValue: (value: GroupValue<T>) => void;
+    unhighlightValue: (value: GroupValue<T>) => void;
+    clearHighlights: () => void;
+    isHighlighted: (value: GroupValue<T>) => boolean;
+    selectByFilter: (filterFn: (value: GroupValue<T>) => boolean) => void;
+    selectLeafNodes: () => void;
+    selectAtDepth: (depth: number) => void;
+}
+//# sourceMappingURL=types.d.ts.map
\ No newline at end of file
diff --git a/dist/types.d.ts.map b/dist/types.d.ts.map
new file mode 100644
index 0000000..ebe2afa
--- /dev/null
+++ b/dist/types.d.ts.map
@@ -0,0 +1 @@
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\ No newline at end of file
diff --git a/dist/types.js b/dist/types.js
new file mode 100644
index 0000000..78a2ef6
--- /dev/null
+++ b/dist/types.js
@@ -0,0 +1,4 @@
+/**
+ * Core type definitions for supergroup
+ */
+export {};
diff --git a/dist/utils/groupHelpers.d.ts b/dist/utils/groupHelpers.d.ts
new file mode 100644
index 0000000..5bf7784
--- /dev/null
+++ b/dist/utils/groupHelpers.d.ts
@@ -0,0 +1,34 @@
+/**
+ * Core helper utilities for grouping operations
+ * These are pure functions without Vue dependencies
+ */
+import type { GroupValue, PathOptions } from '../types';
+/**
+ * Check if entire group list is numeric
+ */
+export declare function isNumericGroup(groups: Record<string, any[]>): boolean;
+/**
+ * Filter out empty values from records
+ */
+export declare function filterOutEmpty<T>(recs: T[], dim: keyof T | ((record: T) => any)): T[];
+/**
+ * Create dimension path string
+ */
+export declare function createDimPath<T>(val: GroupValue<T>, opts?: PathOptions): string;
+/**
+ * Create aggregation function
+ */
+export declare function createAggregator<T, R>(records: T[], func: (values: any[]) => R, field?: keyof T | ((record: T) => any)): R;
+/**
+ * Calculate percentage of parent
+ */
+export declare function calculatePct<T>(records: T[], parentRecords: T[]): number;
+/**
+ * Multi-valued groupBy - allows records to appear in multiple groups
+ */
+export declare function multiValuedGroupBy<T>(recs: T[], dimFunc: (record: T) => (string | number)[]): Record<string, T[]>;
+/**
+ * Find root nodes from hierarchical data (nodes that are parents but not children)
+ */
+export declare function findRootNodes<T>(data: T[], parentProp: keyof T, childProp: keyof T): string[];
+//# sourceMappingURL=groupHelpers.d.ts.map
\ No newline at end of file
diff --git a/dist/utils/groupHelpers.d.ts.map b/dist/utils/groupHelpers.d.ts.map
new file mode 100644
index 0000000..e293c36
--- /dev/null
+++ b/dist/utils/groupHelpers.d.ts.map
@@ -0,0 +1 @@
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\ No newline at end of file
diff --git a/dist/utils/groupHelpers.js b/dist/utils/groupHelpers.js
new file mode 100644
index 0000000..ca19d59
--- /dev/null
+++ b/dist/utils/groupHelpers.js
@@ -0,0 +1,89 @@
+/**
+ * Core helper utilities for grouping operations
+ * These are pure functions without Vue dependencies
+ */
+import _ from 'lodash';
+/**
+ * Check if entire group list is numeric
+ */
+export function isNumericGroup(groups) {
+    return _.every(_.keys(groups), (k) => {
+        return k === null ||
+            k === undefined ||
+            (!isNaN(Number(k))) ||
+            ["null", ".", "undefined"].indexOf(k.toLowerCase()) > -1;
+    });
+}
+/**
+ * Filter out empty values from records
+ */
+export function filterOutEmpty(recs, dim) {
+    const func = _.isFunction(dim) ? dim : (d) => d[dim];
+    return recs.filter(r => !_.isEmpty(func(r)) ||
+        (_.isNumber(func(r)) && isFinite(func(r))));
+}
+/**
+ * Create dimension path string
+ */
+export function createDimPath(val, opts = {}) {
+    const delim = opts.delim || '/';
+    const path = [];
+    let ptr = val;
+    path.push(val);
+    while ((ptr = ptr.parent)) {
+        path.unshift(ptr);
+    }
+    if (opts.noRoot)
+        path.shift();
+    if (opts.backwards)
+        path.reverse();
+    return opts.dimName ?
+        path.map(v => String(v.dim)).join(delim) :
+        path.map(v => String(v.value || v)).join(delim);
+}
+/**
+ * Create aggregation function
+ */
+export function createAggregator(records, func, field) {
+    const values = field
+        ? (_.isFunction(field) ? _.map(records, field) : _.map(records, field))
+        : records;
+    return func(values);
+}
+/**
+ * Calculate percentage of parent
+ */
+export function calculatePct(records, parentRecords) {
+    return records.length / parentRecords.length;
+}
+/**
+ * Multi-valued groupBy - allows records to appear in multiple groups
+ */
+export function multiValuedGroupBy(recs, dimFunc) {
+    const result = {};
+    recs.forEach(rec => {
+        const keys = dimFunc(rec);
+        if (!Array.isArray(keys)) {
+            throw new Error("multiValuedGroupBy requires array keys");
+        }
+        keys.forEach(key => {
+            const keyStr = String(key);
+            if (!result[keyStr]) {
+                result[keyStr] = [];
+            }
+            if (!result[keyStr].includes(rec)) {
+                result[keyStr].push(rec);
+            }
+        });
+    });
+    return result;
+}
+/**
+ * Find root nodes from hierarchical data (nodes that are parents but not children)
+ */
+export function findRootNodes(data, parentProp, childProp) {
+    const byParent = _.groupBy(data, parentProp);
+    const byChild = _.groupBy(data, childProp);
+    // Find root nodes (appear as parent but not as child)
+    return Object.keys(byParent).filter(parent => !byChild[parent]);
+}
diff --git a/examples/VueComponent.vue b/examples/VueComponent.vue
new file mode 100644
index 0000000..863a22c
--- /dev/null
+++ b/examples/VueComponent.vue
@@ -0,0 +1,241 @@
+<!--
+  Example Vue 3 component using Supergroup composables
+  
+  This demonstrates how to use Supergroup in a real Vue application
+  for interactive data grouping and visualization.
+-->
+
+<template>
+  <div class="supergroup-demo">
+    <h1>Olympic Athletes Grouping Demo</h1>
+    
+    <!-- Controls -->
+    <div class="controls">
+      <label>
+        Group By:
+        <select v-model="dimension">
+          <option value="Country">Country</option>
+          <option value="Sport">Sport</option>
+          <option value="Year">Year</option>
+        </select>
+      </label>
+      
+      <label>
+        <input type="checkbox" v-model="multiLevel" />
+        Multi-level (Country > Sport)
+      </label>
+    </div>
+
+    <!-- Stats -->
+    <div class="stats">
+      <p>Total Records: {{ allRecords.length }}</p>
+      <p>Groups: {{ grouped.values.length }}</p>
+      <p v-if="selection.selectedCount.value > 0">
+        Selected: {{ selection.selectedCount.value }} groups, 
+        {{ selection.selectedRecords.value.length }} records
+      </p>
+    </div>
+
+    <!-- Groups List -->
+    <div class="groups">
+      <div 
+        v-for="group in grouped.values" 
+        :key="group.value"
+        class="group"
+        :class="{ selected: selection.isSelected(group) }"
+        @click="selection.toggleValue(group)"
+      >
+        <h3>{{ group.value }}</h3>
+        <p>{{ group.records.length }} athletes</p>
+        
+        <!-- Show children if multi-level -->
+        <div v-if="group.children" class="children">
+          <div 
+            v-for="child in group.children" 
+            :key="child.value"
+            class="child"
+          >
+            {{ child.value }} ({{ child.records.length }})
+          </div>
+        </div>
+      </div>
+    </div>
+
+    <!-- Selected Records -->
+    <div v-if="selection.selectedRecords.value.length > 0" class="selected-records">
+      <h2>Selected Athletes</h2>
+      <table>
+        <thead>
+          <tr>
+            <th>Athlete</th>
+            <th>Country</th>
+            <th>Sport</th>
+            <th>Year</th>
+            <th>Medals</th>
+          </tr>
+        </thead>
+        <tbody>
+          <tr v-for="(record, i) in selection.selectedRecords.value.slice(0, 10)" :key="i">
+            <td>{{ record.Athlete }}</td>
+            <td>{{ record.Country }}</td>
+            <td>{{ record.Sport }}</td>
+            <td>{{ record.Year }}</td>
+            <td>{{ record['Total Medals'] }}</td>
+          </tr>
+        </tbody>
+      </table>
+      <p v-if="selection.selectedRecords.value.length > 10">
+        ... and {{ selection.selectedRecords.value.length - 10 }} more
+      </p>
+    </div>
+  </div>
+</template>
+
+<script setup>
+import { ref, computed, watch } from 'vue';
+import { useGrouping, useGroupSelection } from 'supergroup/composables';
+
+// Sample data (in real app, this would come from API/props)
+const athleteData = ref([
+  {Athlete: "Michael Phelps", Country: "United States", Sport: "Swimming", Year: "2008", "Total Medals": "8"},
+  {Athlete: "Michael Phelps", Country: "United States", Sport: "Swimming", Year: "2004", "Total Medals": "8"},
+  {Athlete: "Usain Bolt", Country: "Jamaica", Sport: "Athletics", Year: "2008", "Total Medals": "3"},
+  {Athlete: "Usain Bolt", Country: "Jamaica", Sport: "Athletics", Year: "2012", "Total Medals": "3"},
+  {Athlete: "Simone Biles", Country: "United States", Sport: "Gymnastics", Year: "2016", "Total Medals": "5"},
+  {Athlete: "Katie Ledecky", Country: "United States", Sport: "Swimming", Year: "2016", "Total Medals": "4"},
+  // ... more data would be here
+]);
+
+// Grouping controls
+const dimension = ref('Country');
+const multiLevel = ref(false);
+
+// Computed dimension for grouping
+const groupDimension = computed(() => {
+  return multiLevel.value ? ['Country', 'Sport'] : dimension.value;
+});
+
+// Create reactive grouping
+const { grouped, allRecords } = useGrouping(athleteData, groupDimension);
+
+// Selection management
+const selection = useGroupSelection(grouped);
+
+// Reset selection when dimension changes
+watch(groupDimension, () => {
+  selection.clearSelection();
+});
+</script>
+
+<style scoped>
+.supergroup-demo {
+  font-family: Arial, sans-serif;
+  max-width: 1200px;
+  margin: 0 auto;
+  padding: 20px;
+}
+
+.controls {
+  background: #f5f5f5;
+  padding: 15px;
+  margin: 20px 0;
+  border-radius: 4px;
+}
+
+.controls label {
+  margin-right: 20px;
+}
+
+.controls select {
+  padding: 5px;
+  margin-left: 5px;
+}
+
+.stats {
+  background: #e3f2fd;
+  padding: 15px;
+  margin: 20px 0;
+  border-radius: 4px;
+}
+
+.stats p {
+  margin: 5px 0;
+}
+
+.groups {
+  display: grid;
+  grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
+  gap: 15px;
+  margin: 20px 0;
+}
+
+.group {
+  border: 2px solid #ddd;
+  padding: 15px;
+  border-radius: 4px;
+  cursor: pointer;
+  transition: all 0.2s;
+}
+
+.group:hover {
+  border-color: #2196f3;
+  box-shadow: 0 2px 8px rgba(0,0,0,0.1);
+}
+
+.group.selected {
+  border-color: #2196f3;
+  background-color: #e3f2fd;
+}
+
+.group h3 {
+  margin: 0 0 10px 0;
+  color: #1976d2;
+}
+
+.group p {
+  margin: 0;
+  color: #666;
+}
+
+.children {
+  margin-top: 10px;
+  padding-top: 10px;
+  border-top: 1px solid #ddd;
+}
+
+.child {
+  padding: 5px;
+  margin: 2px 0;
+  background: white;
+  border-radius: 2px;
+  font-size: 0.9em;
+}
+
+.selected-records {
+  margin-top: 30px;
+  border-top: 2px solid #ddd;
+  padding-top: 20px;
+}
+
+.selected-records table {
+  width: 100%;
+  border-collapse: collapse;
+  margin: 15px 0;
+}
+
+.selected-records th,
+.selected-records td {
+  padding: 10px;
+  text-align: left;
+  border-bottom: 1px solid #ddd;
+}
+
+.selected-records th {
+  background: #f5f5f5;
+  font-weight: bold;
+}
+
+.selected-records tr:hover {
+  background: #f9f9f9;
+}
+</style>
diff --git a/package-lock.json b/package-lock.json
index 82509ae..91e0300 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1,22 +1,217 @@
 {
   "name": "supergroup",
-  "version": "1.1.9",
+  "version": "2.0.0",
   "lockfileVersion": 3,
   "requires": true,
   "packages": {
     "": {
       "name": "supergroup",
-      "version": "1.1.9",
+      "version": "2.0.0",
       "license": "MIT",
       "dependencies": {
         "lodash": "^4.17.4"
       },
       "devDependencies": {
+        "@types/lodash": "^4.17.23",
+        "@types/node": "^25.0.9",
         "jasmine": "^2.2.1",
+        "typescript": "^5.9.3",
         "vows": "^0.8.1",
+        "vue": "^3.5.27",
         "xhr2": "^0.1.3"
+      },
+      "peerDependencies": {
+        "vue": "^3.0.0"
+      },
+      "peerDependenciesMeta": {
+        "vue": {
+          "optional": true
+        }
+      }
+    },
+    "node_modules/@babel/helper-string-parser": {
+      "version": "7.27.1",
+      "resolved": "https://registry.npmjs.org/@babel/helper-string-parser/-/helper-string-parser-7.27.1.tgz",
+      "integrity": "sha512-qMlSxKbpRlAridDExk92nSobyDdpPijUq2DW6oDnUqd0iOGxmQjyqhMIihI9+zv4LPyZdRje2cavWPbCbWm3eA==",
+      "dev": true,
+      "license": "MIT",
+      "engines": {
+        "node": ">=6.9.0"
+      }
+    },
+    "node_modules/@babel/helper-validator-identifier": {
+      "version": "7.28.5",
+      "resolved": "https://registry.npmjs.org/@babel/helper-validator-identifier/-/helper-validator-identifier-7.28.5.tgz",
+      "integrity": "sha512-qSs4ifwzKJSV39ucNjsvc6WVHs6b7S03sOh2OcHF9UHfVPqWWALUsNUVzhSBiItjRZoLHx7nIarVjqKVusUZ1Q==",
+      "dev": true,
+      "license": "MIT",
+      "engines": {
+        "node": ">=6.9.0"
+      }
+    },
+    "node_modules/@babel/parser": {
+      "version": "7.28.6",
+      "resolved": "https://registry.npmjs.org/@babel/parser/-/parser-7.28.6.tgz",
+      "integrity": "sha512-TeR9zWR18BvbfPmGbLampPMW+uW1NZnJlRuuHso8i87QZNq2JRF9i6RgxRqtEq+wQGsS19NNTWr2duhnE49mfQ==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "@babel/types": "^7.28.6"
+      },
+      "bin": {
+        "parser": "bin/babel-parser.js"
+      },
+      "engines": {
+        "node": ">=6.0.0"
+      }
+    },
+    "node_modules/@babel/types": {
+      "version": "7.28.6",
+      "resolved": "https://registry.npmjs.org/@babel/types/-/types-7.28.6.tgz",
+      "integrity": "sha512-0ZrskXVEHSWIqZM/sQZ4EV3jZJXRkio/WCxaqKZP1g//CEWEPSfeZFcms4XeKBCHU0ZKnIkdJeU/kF+eRp5lBg==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "@babel/helper-string-parser": "^7.27.1",
+        "@babel/helper-validator-identifier": "^7.28.5"
+      },
+      "engines": {
+        "node": ">=6.9.0"
+      }
+    },
+    "node_modules/@jridgewell/sourcemap-codec": {
+      "version": "1.5.5",
+      "resolved": "https://registry.npmjs.org/@jridgewell/sourcemap-codec/-/sourcemap-codec-1.5.5.tgz",
+      "integrity": "sha512-cYQ9310grqxueWbl+WuIUIaiUaDcj7WOq5fVhEljNVgRfOUhY9fy2zTvfoqWsnebh8Sl70VScFbICvJnLKB0Og==",
+      "dev": true,
+      "license": "MIT"
+    },
+    "node_modules/@types/lodash": {
+      "version": "4.17.23",
+      "resolved": "https://registry.npmjs.org/@types/lodash/-/lodash-4.17.23.tgz",
+      "integrity": "sha512-RDvF6wTulMPjrNdCoYRC8gNR880JNGT8uB+REUpC2Ns4pRqQJhGz90wh7rgdXDPpCczF3VGktDuFGVnz8zP7HA==",
+      "dev": true,
+      "license": "MIT"
+    },
+    "node_modules/@types/node": {
+      "version": "25.0.9",
+      "resolved": "https://registry.npmjs.org/@types/node/-/node-25.0.9.tgz",
+      "integrity": "sha512-/rpCXHlCWeqClNBwUhDcusJxXYDjZTyE8v5oTO7WbL8eij2nKhUeU89/6xgjU7N4/Vh3He0BtyhJdQbDyhiXAw==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "undici-types": "~7.16.0"
+      }
+    },
+    "node_modules/@vue/compiler-core": {
+      "version": "3.5.27",
+      "resolved": "https://registry.npmjs.org/@vue/compiler-core/-/compiler-core-3.5.27.tgz",
+      "integrity": "sha512-gnSBQjZA+//qDZen+6a2EdHqJ68Z7uybrMf3SPjEGgG4dicklwDVmMC1AeIHxtLVPT7sn6sH1KOO+tS6gwOUeQ==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "@babel/parser": "^7.28.5",
+        "@vue/shared": "3.5.27",
+        "entities": "^7.0.0",
+        "estree-walker": "^2.0.2",
+        "source-map-js": "^1.2.1"
       }
     },
+    "node_modules/@vue/compiler-dom": {
+      "version": "3.5.27",
+      "resolved": "https://registry.npmjs.org/@vue/compiler-dom/-/compiler-dom-3.5.27.tgz",
+      "integrity": "sha512-oAFea8dZgCtVVVTEC7fv3T5CbZW9BxpFzGGxC79xakTr6ooeEqmRuvQydIiDAkglZEAd09LgVf1RoDnL54fu5w==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "@vue/compiler-core": "3.5.27",
+        "@vue/shared": "3.5.27"
+      }
+    },
+    "node_modules/@vue/compiler-sfc": {
+      "version": "3.5.27",
+      "resolved": "https://registry.npmjs.org/@vue/compiler-sfc/-/compiler-sfc-3.5.27.tgz",
+      "integrity": "sha512-sHZu9QyDPeDmN/MRoshhggVOWE5WlGFStKFwu8G52swATgSny27hJRWteKDSUUzUH+wp+bmeNbhJnEAel/auUQ==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "@babel/parser": "^7.28.5",
+        "@vue/compiler-core": "3.5.27",
+        "@vue/compiler-dom": "3.5.27",
+        "@vue/compiler-ssr": "3.5.27",
+        "@vue/shared": "3.5.27",
+        "estree-walker": "^2.0.2",
+        "magic-string": "^0.30.21",
+        "postcss": "^8.5.6",
+        "source-map-js": "^1.2.1"
+      }
+    },
+    "node_modules/@vue/compiler-ssr": {
+      "version": "3.5.27",
+      "resolved": "https://registry.npmjs.org/@vue/compiler-ssr/-/compiler-ssr-3.5.27.tgz",
+      "integrity": "sha512-Sj7h+JHt512fV1cTxKlYhg7qxBvack+BGncSpH+8vnN+KN95iPIcqB5rsbblX40XorP+ilO7VIKlkuu3Xq2vjw==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "@vue/compiler-dom": "3.5.27",
+        "@vue/shared": "3.5.27"
+      }
+    },
+    "node_modules/@vue/reactivity": {
+      "version": "3.5.27",
+      "resolved": "https://registry.npmjs.org/@vue/reactivity/-/reactivity-3.5.27.tgz",
+      "integrity": "sha512-vvorxn2KXfJ0nBEnj4GYshSgsyMNFnIQah/wczXlsNXt+ijhugmW+PpJ2cNPe4V6jpnBcs0MhCODKllWG+nvoQ==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "@vue/shared": "3.5.27"
+      }
+    },
+    "node_modules/@vue/runtime-core": {
+      "version": "3.5.27",
+      "resolved": "https://registry.npmjs.org/@vue/runtime-core/-/runtime-core-3.5.27.tgz",
+      "integrity": "sha512-fxVuX/fzgzeMPn/CLQecWeDIFNt3gQVhxM0rW02Tvp/YmZfXQgcTXlakq7IMutuZ/+Ogbn+K0oct9J3JZfyk3A==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "@vue/reactivity": "3.5.27",
+        "@vue/shared": "3.5.27"
+      }
+    },
+    "node_modules/@vue/runtime-dom": {
+      "version": "3.5.27",
+      "resolved": "https://registry.npmjs.org/@vue/runtime-dom/-/runtime-dom-3.5.27.tgz",
+      "integrity": "sha512-/QnLslQgYqSJ5aUmb5F0z0caZPGHRB8LEAQ1s81vHFM5CBfnun63rxhvE/scVb/j3TbBuoZwkJyiLCkBluMpeg==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "@vue/reactivity": "3.5.27",
+        "@vue/runtime-core": "3.5.27",
+        "@vue/shared": "3.5.27",
+        "csstype": "^3.2.3"
+      }
+    },
+    "node_modules/@vue/server-renderer": {
+      "version": "3.5.27",
+      "resolved": "https://registry.npmjs.org/@vue/server-renderer/-/server-renderer-3.5.27.tgz",
+      "integrity": "sha512-qOz/5thjeP1vAFc4+BY3Nr6wxyLhpeQgAE/8dDtKo6a6xdk+L4W46HDZgNmLOBUDEkFXV3G7pRiUqxjX0/2zWA==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "@vue/compiler-ssr": "3.5.27",
+        "@vue/shared": "3.5.27"
+      },
+      "peerDependencies": {
+        "vue": "3.5.27"
+      }
+    },
+    "node_modules/@vue/shared": {
+      "version": "3.5.27",
+      "resolved": "https://registry.npmjs.org/@vue/shared/-/shared-3.5.27.tgz",
+      "integrity": "sha512-dXr/3CgqXsJkZ0n9F3I4elY8wM9jMJpP3pvRG52r6m0tu/MsAFIe6JpXVGeNMd/D9F4hQynWT8Rfuj0bdm9kFQ==",
+      "dev": true,
+      "license": "MIT"
+    },
     "node_modules/balanced-match": {
       "version": "1.0.2",
       "resolved": "https://registry.npmjs.org/balanced-match/-/balanced-match-1.0.2.tgz",
@@ -39,6 +234,13 @@
       "integrity": "sha512-/Srv4dswyQNBfohGpz9o6Yb3Gz3SrUDqBH5rTuhGR7ahtlbYKnVxw2bCFMRljaA7EXHaXZ8wsHdodFvbkhKmqg==",
       "dev": true
     },
+    "node_modules/csstype": {
+      "version": "3.2.3",
+      "resolved": "https://registry.npmjs.org/csstype/-/csstype-3.2.3.tgz",
+      "integrity": "sha512-z1HGKcYy2xA8AGQfwrn0PAy+PB7X/GSj3UVJW9qKyn43xWa+gl5nXmU4qqLMRzWVLFC8KusUX8T/0kCiOYpAIQ==",
+      "dev": true,
+      "license": "MIT"
+    },
     "node_modules/diff": {
       "version": "4.0.2",
       "resolved": "https://registry.npmjs.org/diff/-/diff-4.0.2.tgz",
@@ -48,6 +250,26 @@
         "node": ">=0.3.1"
       }
     },
+    "node_modules/entities": {
+      "version": "7.0.0",
+      "resolved": "https://registry.npmjs.org/entities/-/entities-7.0.0.tgz",
+      "integrity": "sha512-FDWG5cmEYf2Z00IkYRhbFrwIwvdFKH07uV8dvNy0omp/Qb1xcyCWp2UDtcwJF4QZZvk0sLudP6/hAu42TaqVhQ==",
+      "dev": true,
+      "license": "BSD-2-Clause",
+      "engines": {
+        "node": ">=0.12"
+      },
+      "funding": {
+        "url": "https://github.com/fb55/entities?sponsor=1"
+      }
+    },
+    "node_modules/estree-walker": {
+      "version": "2.0.2",
+      "resolved": "https://registry.npmjs.org/estree-walker/-/estree-walker-2.0.2.tgz",
+      "integrity": "sha512-Rfkk/Mp/DL7JVje3u18FxFujQlTNR2q6QfMSMB7AvCBx91NGj/ba3kCfza0f6dVDbw7YlRf/nDrn7pQrCCyQ/w==",
+      "dev": true,
+      "license": "MIT"
+    },
     "node_modules/exit": {
       "version": "0.1.2",
       "resolved": "https://registry.npmjs.org/exit/-/exit-0.1.2.tgz",
@@ -133,6 +355,16 @@
       "resolved": "https://registry.npmjs.org/lodash/-/lodash-4.17.21.tgz",
       "integrity": "sha512-v2kDEe57lecTulaDIuNTPy3Ry4gLGJ6Z1O3vE1krgXZNrsQ+LFTGHVxVjcXPs17LhbZVGedAJv8XZ1tvj5FvSg=="
     },
+    "node_modules/magic-string": {
+      "version": "0.30.21",
+      "resolved": "https://registry.npmjs.org/magic-string/-/magic-string-0.30.21.tgz",
+      "integrity": "sha512-vd2F4YUyEXKGcLHoq+TEyCjxueSeHnFxyyjNp80yg0XV4vUhnDer/lvvlqM/arB5bXQN5K2/3oinyCRyx8T2CQ==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "@jridgewell/sourcemap-codec": "^1.5.5"
+      }
+    },
     "node_modules/minimatch": {
       "version": "3.1.2",
       "resolved": "https://registry.npmjs.org/minimatch/-/minimatch-3.1.2.tgz",
@@ -145,6 +377,25 @@
         "node": "*"
       }
     },
+    "node_modules/nanoid": {
+      "version": "3.3.11",
+      "resolved": "https://registry.npmjs.org/nanoid/-/nanoid-3.3.11.tgz",
+      "integrity": "sha512-N8SpfPUnUp1bK+PMYW8qSWdl9U+wwNWI4QKxOYDy9JAro3WMX7p2OeVRF9v+347pnakNevPmiHhNmZ2HbFA76w==",
+      "dev": true,
+      "funding": [
+        {
+          "type": "github",
+          "url": "https://github.com/sponsors/ai"
+        }
+      ],
+      "license": "MIT",
+      "bin": {
+        "nanoid": "bin/nanoid.cjs"
+      },
+      "engines": {
+        "node": "^10 || ^12 || ^13.7 || ^14 || >=15.0.1"
+      }
+    },
     "node_modules/once": {
       "version": "1.4.0",
       "resolved": "https://registry.npmjs.org/once/-/once-1.4.0.tgz",
@@ -163,6 +414,73 @@
         "node": ">=0.10.0"
       }
     },
+    "node_modules/picocolors": {
+      "version": "1.1.1",
+      "resolved": "https://registry.npmjs.org/picocolors/-/picocolors-1.1.1.tgz",
+      "integrity": "sha512-xceH2snhtb5M9liqDsmEw56le376mTZkEX/jEb/RxNFyegNul7eNslCXP9FDj/Lcu0X8KEyMceP2ntpaHrDEVA==",
+      "dev": true,
+      "license": "ISC"
+    },
+    "node_modules/postcss": {
+      "version": "8.5.6",
+      "resolved": "https://registry.npmjs.org/postcss/-/postcss-8.5.6.tgz",
+      "integrity": "sha512-3Ybi1tAuwAP9s0r1UQ2J4n5Y0G05bJkpUIO0/bI9MhwmD70S5aTWbXGBwxHrelT+XM1k6dM0pk+SwNkpTRN7Pg==",
+      "dev": true,
+      "funding": [
+        {
+          "type": "opencollective",
+          "url": "https://opencollective.com/postcss/"
+        },
+        {
+          "type": "tidelift",
+          "url": "https://tidelift.com/funding/github/npm/postcss"
+        },
+        {
+          "type": "github",
+          "url": "https://github.com/sponsors/ai"
+        }
+      ],
+      "license": "MIT",
+      "dependencies": {
+        "nanoid": "^3.3.11",
+        "picocolors": "^1.1.1",
+        "source-map-js": "^1.2.1"
+      },
+      "engines": {
+        "node": "^10 || ^12 || >=14"
+      }
+    },
+    "node_modules/source-map-js": {
+      "version": "1.2.1",
+      "resolved": "https://registry.npmjs.org/source-map-js/-/source-map-js-1.2.1.tgz",
+      "integrity": "sha512-UXWMKhLOwVKb728IUtQPXxfYU+usdybtUrK/8uGE8CQMvrhOpwvzDBwj0QhSL7MQc7vIsISBG8VQ8+IDQxpfQA==",
+      "dev": true,
+      "license": "BSD-3-Clause",
+      "engines": {
+        "node": ">=0.10.0"
+      }
+    },
+    "node_modules/typescript": {
+      "version": "5.9.3",
+      "resolved": "https://registry.npmjs.org/typescript/-/typescript-5.9.3.tgz",
+      "integrity": "sha512-jl1vZzPDinLr9eUt3J/t7V6FgNEw9QjvBPdysz9KfQDD41fQrC2Y4vKQdiaUpFT4bXlb1RHhLpp8wtm6M5TgSw==",
+      "dev": true,
+      "license": "Apache-2.0",
+      "bin": {
+        "tsc": "bin/tsc",
+        "tsserver": "bin/tsserver"
+      },
+      "engines": {
+        "node": ">=14.17"
+      }
+    },
+    "node_modules/undici-types": {
+      "version": "7.16.0",
+      "resolved": "https://registry.npmjs.org/undici-types/-/undici-types-7.16.0.tgz",
+      "integrity": "sha512-Zz+aZWSj8LE6zoxD+xrjh4VfkIG8Ya6LvYkZqtUQGJPZjYl53ypCaUwWqo7eI0x66KBGeRo+mlBEkMSeSZ38Nw==",
+      "dev": true,
+      "license": "MIT"
+    },
     "node_modules/vows": {
       "version": "0.8.3",
       "resolved": "https://registry.npmjs.org/vows/-/vows-0.8.3.tgz",
@@ -177,6 +495,28 @@
         "vows": "bin/vows"
       }
     },
+    "node_modules/vue": {
+      "version": "3.5.27",
+      "resolved": "https://registry.npmjs.org/vue/-/vue-3.5.27.tgz",
+      "integrity": "sha512-aJ/UtoEyFySPBGarREmN4z6qNKpbEguYHMmXSiOGk69czc+zhs0NF6tEFrY8TZKAl8N/LYAkd4JHVd5E/AsSmw==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "@vue/compiler-dom": "3.5.27",
+        "@vue/compiler-sfc": "3.5.27",
+        "@vue/runtime-dom": "3.5.27",
+        "@vue/server-renderer": "3.5.27",
+        "@vue/shared": "3.5.27"
+      },
+      "peerDependencies": {
+        "typescript": "*"
+      },
+      "peerDependenciesMeta": {
+        "typescript": {
+          "optional": true
+        }
+      }
+    },
     "node_modules/wrappy": {
       "version": "1.0.2",
       "resolved": "https://registry.npmjs.org/wrappy/-/wrappy-1.0.2.tgz",
diff --git a/package.json b/package.json
index 6c5e2ed..c156060 100644
--- a/package.json
+++ b/package.json
@@ -1,12 +1,42 @@
 {
   "name": "supergroup",
-  "version": "1.1.9",
-  "description": "Nested groups on arrays of objects where groups are Strings that know what you want them to know about themselves and their relatives.",
-  "main": "supergroup.js",
+  "version": "2.0.0",
+  "description": "Nested groups on arrays of objects where groups are Strings that know what you want them to know about themselves and their relatives. Now with Vue.js composables!",
+  "main": "supergroup.cjs",
+  "module": "dist/index.js",
+  "types": "dist/index.d.ts",
+  "type": "module",
+  "exports": {
+    ".": {
+      "types": "./dist/index.d.ts",
+      "import": "./dist/index.js",
+      "require": "./supergroup.cjs"
+    },
+    "./composables": {
+      "types": "./dist/index.d.ts",
+      "import": "./dist/index.js"
+    },
+    "./legacy": {
+      "require": "./supergroup.cjs"
+    }
+  },
   "scripts": {
-    "test": "vows test/*.js --spec",
-    "debug": "node --inspect --debug-brk test/supergroup_vows.js"
+    "build": "tsc",
+    "build:watch": "tsc --watch",
+    "test": "vows test/*.cjs --spec",
+    "test:composables": "node test/composables.test.js",
+    "test:all": "npm run test && npm run test:composables",
+    "debug": "node --inspect --debug-brk test/supergroup_vows.cjs",
+    "prepublishOnly": "npm run build"
   },
+  "files": [
+    "dist",
+    "src",
+    "supergroup.cjs",
+    "README.md",
+    "COMPOSABLES.md",
+    "LICENSE"
+  ],
   "repository": {
     "type": "git",
     "url": "https://github.com/Sigfried/supergroup.git"
@@ -20,7 +50,11 @@
     "convenience",
     "readability",
     "data",
-    "hierarchy"
+    "hierarchy",
+    "vue",
+    "vue3",
+    "composables",
+    "reactive"
   ],
   "author": "Sigfried Gold",
   "license": "MIT",
@@ -31,9 +65,21 @@
   "dependencies": {
     "lodash": "^4.17.4"
   },
+  "peerDependencies": {
+    "vue": "^3.0.0"
+  },
+  "peerDependenciesMeta": {
+    "vue": {
+      "optional": true
+    }
+  },
   "devDependencies": {
+    "@types/lodash": "^4.17.23",
+    "@types/node": "^25.0.9",
     "jasmine": "^2.2.1",
+    "typescript": "^5.9.3",
     "vows": "^0.8.1",
+    "vue": "^3.5.27",
     "xhr2": "^0.1.3"
   }
 }
diff --git a/src/composables/useGroupList.js b/src/composables/useGroupList.js
new file mode 100644
index 0000000..e8c08fa
--- /dev/null
+++ b/src/composables/useGroupList.js
@@ -0,0 +1,313 @@
+/**
+ * Composable for working with group lists
+ * Provides lookup, sorting, aggregation, and navigation
+ */
+
+import { computed, ref, unref, isRef } from 'vue';
+import _ from 'lodash';
+
+/**
+ * Group list composable
+ * @param {Object} groupResult - Result from useGrouping (can be a computed ref)
+ * @returns {Object} List operations and utilities
+ */
+export function useGroupList(groupResult) {
+  // Keep reactivity - if it's a ref, use it directly
+  const groupRef = isRef(groupResult) ? groupResult : ref(groupResult);
+
+  /**
+   * Get values array
+   */
+  const values = computed(() => {
+    const group = groupRef.value;
+    return group.values || [];
+  });
+
+  /**
+   * Get child property name
+   */
+  const childProp = computed(() => {
+    const group = groupRef.value;
+    return group.childProp || 'children';
+  });
+
+  /**
+   * Lookup single value
+   */
+  const singleLookup = (query) => {
+    return values.value.find(v => v.value == query);
+  };
+
+  /**
+   * Lookup value or path
+   */
+  const lookup = (query) => {
+    if (Array.isArray(query)) {
+      // Path lookup for hierarchical groups
+      let result = singleLookup(query[0]);
+      
+      for (let i = 1; i < query.length && result; i++) {
+        const children = result[childProp.value];
+        if (!children) break;
+        result = children.find(v => v.value == query[i]);
+      }
+      
+      return result;
+    } else {
+      // Single value lookup
+      return singleLookup(query);
+    }
+  };
+
+  /**
+   * Lookup multiple values
+   */
+  const lookupMany = (queries) => {
+    return queries
+      .map(q => singleLookup(q))
+      .filter(v => v !== undefined);
+  };
+
+  /**
+   * Get raw values array
+   */
+  const rawValues = computed(() => {
+    return values.value.map(v => v.value);
+  });
+
+  /**
+   * Flatten entire tree into single array
+   */
+  const flattenTree = computed(() => {
+    const result = [];
+    const prop = childProp.value;
+    
+    const flatten = (vals) => {
+      vals.forEach(val => {
+        result.push(val);
+        if (val[prop] && val[prop].length > 0) {
+          flatten(val[prop]);
+        }
+      });
+    };
+    
+    flatten(values.value);
+    return result;
+  });
+
+  /**
+   * Get all leaf nodes
+   */
+  const leafNodes = computed(() => {
+    const prop = childProp.value;
+    return flattenTree.value.filter(v => 
+      !v[prop] || v[prop].length === 0
+    );
+  });
+
+  /**
+   * Get nodes at specific level
+   */
+  const nodesAtLevel = (level) => {
+    if (level === 0) return values.value;
+    
+    const result = [];
+    const prop = childProp.value;
+    
+    const traverse = (vals, currentLevel) => {
+      if (currentLevel === level) {
+        result.push(...vals);
+        return;
+      }
+      
+      vals.forEach(v => {
+        if (v[prop] && v[prop].length > 0) {
+          traverse(v[prop], currentLevel + 1);
+        }
+      });
+    };
+    
+    traverse(values.value, 0);
+    return result;
+  };
+
+  /**
+   * Get name paths for all values
+   */
+  const namePaths = (opts = {}) => {
+    const delim = opts.delim || '/';
+    
+    return values.value.map(v => {
+      const path = [];
+      let ptr = v;
+      
+      path.push(ptr.value);
+      while (ptr.parent) {
+        ptr = ptr.parent;
+        path.unshift(ptr.value);
+      }
+      
+      if (opts.noRoot) path.shift();
+      if (opts.backwards) path.reverse();
+      
+      return path.join(delim);
+    });
+  };
+
+  /**
+   * Apply aggregation to all values
+   */
+  const aggregates = (func, field, returnType = 'array') => {
+    const results = values.value.map(val => {
+      if (_.isFunction(field)) {
+        return func(_.map(val.records, field));
+      }
+      return func(_.map(val.records, field));
+    });
+
+    if (returnType === 'dict') {
+      return _.zipObject(rawValues.value, results);
+    }
+    
+    return results;
+  };
+
+  /**
+   * Sort values
+   */
+  const sort = (compareFn) => {
+    return [...values.value].sort(compareFn);
+  };
+
+  /**
+   * Sort values by function
+   */
+  const sortBy = (iteratee) => {
+    return _.sortBy(values.value, iteratee);
+  };
+
+  /**
+   * Convert to D3 nest entries format
+   */
+  const toD3Entries = () => {
+    const prop = childProp.value;
+    
+    const convert = (vals) => {
+      return vals.map(val => {
+        if (val[prop] && val[prop].length > 0) {
+          return {
+            key: String(val.value),
+            values: convert(val[prop])
+          };
+        }
+        return {
+          key: String(val.value),
+          values: val.records
+        };
+      });
+    };
+    
+    return convert(values.value);
+  };
+
+  /**
+   * Convert to D3 nest map format
+   */
+  const toD3Map = () => {
+    const prop = childProp.value;
+    
+    const convert = (vals) => {
+      const result = {};
+      
+      vals.forEach(val => {
+        const key = String(val.value);
+        if (val[prop] && val[prop].length > 0) {
+          result[key] = convert(val[prop]);
+        } else {
+          result[key] = [...val.records];
+        }
+      });
+      
+      return result;
+    };
+    
+    return convert(values.value);
+  };
+
+  /**
+   * Create root value wrapper
+   */
+  const asRootVal = (name = 'Root', dimName = 'root') => {
+    const prop = childProp.value;
+    const group = groupRef.value;
+    
+    const rootVal = {
+      value: name,
+      dim: dimName,
+      depth: 0,
+      records: group.records,
+      parent: null,
+      [prop]: values.value
+    };
+
+    // Update children to reference new root
+    values.value.forEach(v => {
+      v.parent = rootVal;
+      // Update all descendant depths
+      const updateDepth = (val, increment) => {
+        val.depth += increment;
+        if (val[prop]) {
+          val[prop].forEach(child => updateDepth(child, increment));
+        }
+      };
+      updateDepth(v, 1);
+    });
+
+    return rootVal;
+  };
+
+  /**
+   * Get summary string for debugging
+   */
+  const summary = (depth = 0) => {
+    const group = groupRef.value;
+    const prop = childProp.value;
+    const indent = '    '.repeat(depth);
+    const dim = group.dim || 'unknown';
+    const vals = values.value.length;
+    const recs = group.records ? group.records.length : 0;
+
+    const lines = [`${indent}${dim}, ${recs} recs (${depth}) ${vals} vals:`];
+    
+    values.value.forEach(val => {
+      const valRecs = val.records ? val.records.length : 0;
+      const valIndent = '    '.repeat(depth + 1);
+      lines.push(`${valIndent}${val.value}, ${valRecs} recs`);
+      
+      if (val[prop] && val[prop].length > 0) {
+        // Recursively summarize children
+        lines.push(`${valIndent}has ${val[prop].length} children`);
+      }
+    });
+
+    return lines.join('\n');
+  };
+
+  return {
+    values,
+    lookup,
+    lookupMany,
+    rawValues,
+    flattenTree,
+    leafNodes,
+    nodesAtLevel,
+    namePaths,
+    aggregates,
+    sort,
+    sortBy,
+    toD3Entries,
+    toD3Map,
+    asRootVal,
+    summary
+  };
+}
diff --git a/src/composables/useGroupList.ts b/src/composables/useGroupList.ts
new file mode 100644
index 0000000..619b763
--- /dev/null
+++ b/src/composables/useGroupList.ts
@@ -0,0 +1,334 @@
+/**
+ * Composable for working with group lists
+ * Provides lookup, sorting, aggregation, and navigation
+ */
+
+import { computed, ref, isRef, type Ref, type ComputedRef } from 'vue';
+import _ from 'lodash';
+import type {
+  GroupResult,
+  GroupValue,
+  PathOptions,
+  D3NestEntry,
+  D3NestMap,
+  UseGroupListReturn
+} from '../types';
+
+/**
+ * Group list composable
+ * @param groupResult - Result from useGrouping (can be a computed ref)
+ * @returns List operations and utilities
+ */
+export function useGroupList<T extends Record<string, any>>(
+  groupResult: GroupResult<T> | Ref<GroupResult<T>> | ComputedRef<GroupResult<T>>
+): UseGroupListReturn<T> {
+  // Keep reactivity - if it's a ref, use it directly
+  const groupRef = isRef(groupResult) ? groupResult : ref(groupResult);
+
+  /**
+   * Get values array
+   */
+  const values = computed(() => {
+    const group = groupRef.value;
+    return (group.values || []) as GroupValue<T>[];
+  });
+
+  /**
+   * Get child property name
+   */
+  const childProp: ComputedRef<string> = computed(() => {
+    const group = groupRef.value;
+    return group.childProp || 'children';
+  });
+
+  /**
+   * Lookup single value
+   */
+  const singleLookup = (query: string | number): GroupValue<T> | undefined => {
+    return values.value.find(v => v.value == query);
+  };
+
+  /**
+   * Lookup value or path
+   */
+  const lookup = (query: string | number | (string | number)[]): GroupValue<T> | undefined => {
+    if (Array.isArray(query)) {
+      // Path lookup for hierarchical groups
+      let result = singleLookup(query[0]);
+      
+      for (let i = 1; i < query.length && result; i++) {
+        const children = result[childProp.value] as GroupValue<T>[];
+        if (!children) break;
+        result = children.find(v => v.value == query[i]);
+      }
+      
+      return result;
+    } else {
+      // Single value lookup
+      return singleLookup(query);
+    }
+  };
+
+  /**
+   * Lookup multiple values
+   */
+  const lookupMany = (queries: (string | number)[]): GroupValue<T>[] => {
+    return queries
+      .map(q => singleLookup(q))
+      .filter((v): v is GroupValue<T> => v !== undefined);
+  };
+
+  /**
+   * Get raw values array
+   */
+  const rawValues: ComputedRef<(string | number)[]> = computed(() => {
+    return values.value.map(v => v.value);
+  });
+
+  /**
+   * Flatten entire tree into single array
+   */
+  const flattenTree: ComputedRef<GroupValue<T>[]> = computed(() => {
+    const result: GroupValue<T>[] = [];
+    const prop = childProp.value;
+    
+    const flatten = (vals: GroupValue<T>[]) => {
+      vals.forEach(val => {
+        result.push(val);
+        const children = val[prop] as GroupValue<T>[];
+        if (children && children.length > 0) {
+          flatten(children);
+        }
+      });
+    };
+    
+    flatten(values.value);
+    return result;
+  });
+
+  /**
+   * Get all leaf nodes
+   */
+  const leafNodes: ComputedRef<GroupValue<T>[]> = computed(() => {
+    const prop = childProp.value;
+    return flattenTree.value.filter(v => {
+      const children = v[prop] as GroupValue<T>[];
+      return !children || children.length === 0;
+    });
+  });
+
+  /**
+   * Get nodes at specific level
+   */
+  const nodesAtLevel = (level: number): GroupValue<T>[] => {
+    if (level === 0) return values.value;
+    
+    const result: GroupValue<T>[] = [];
+    const prop = childProp.value;
+    
+    const traverse = (vals: GroupValue<T>[], currentLevel: number) => {
+      if (currentLevel === level) {
+        result.push(...vals);
+        return;
+      }
+      
+      vals.forEach(v => {
+        const children = v[prop] as GroupValue<T>[];
+        if (children && children.length > 0) {
+          traverse(children, currentLevel + 1);
+        }
+      });
+    };
+    
+    traverse(values.value, 0);
+    return result;
+  };
+
+  /**
+   * Get name paths for all values
+   */
+  const namePaths = (opts: PathOptions = {}): string[] => {
+    const delim = opts.delim || '/';
+    
+    return values.value.map(v => {
+      const path: (string | number)[] = [];
+      let ptr: GroupValue<T> | null = v;
+      
+      path.push(ptr.value);
+      while (ptr.parent) {
+        ptr = ptr.parent;
+        path.unshift(ptr.value);
+      }
+      
+      if (opts.noRoot) path.shift();
+      if (opts.backwards) path.reverse();
+      
+      return path.join(delim);
+    });
+  };
+
+  /**
+   * Apply aggregation to all values
+   */
+  const aggregates = <R>(
+    func: (values: any[]) => R,
+    field?: keyof T | ((record: T) => any),
+    returnType: 'array' | 'dict' = 'array'
+  ): R[] | Record<string | number, R> => {
+    const results = values.value.map(val => {
+      const fieldValues = field
+        ? (_.isFunction(field) ? _.map(val.records, field) : _.map(val.records, field))
+        : val.records;
+      return func(fieldValues);
+    });
+
+    if (returnType === 'dict') {
+      return _.zipObject(rawValues.value, results) as Record<string | number, R>;
+    }
+    
+    return results;
+  };
+
+  /**
+   * Sort values
+   */
+  const sort = (compareFn: (a: GroupValue<T>, b: GroupValue<T>) => number): GroupValue<T>[] => {
+    return [...values.value].sort(compareFn);
+  };
+
+  /**
+   * Sort values by function
+   */
+  const sortBy = (iteratee: ((value: GroupValue<T>) => any) | keyof GroupValue<T>): GroupValue<T>[] => {
+    return _.sortBy(values.value, iteratee as any);
+  };
+
+  /**
+   * Convert to D3 nest entries format
+   */
+  const toD3Entries = (): D3NestEntry<T>[] => {
+    const prop = childProp.value;
+    
+    const convert = (vals: GroupValue<T>[]): D3NestEntry<T>[] => {
+      return vals.map(val => {
+        const children = val[prop] as GroupValue<T>[];
+        if (children && children.length > 0) {
+          return {
+            key: String(val.value),
+            values: convert(children)
+          };
+        }
+        return {
+          key: String(val.value),
+          values: val.records
+        };
+      });
+    };
+    
+    return convert(values.value);
+  };
+
+  /**
+   * Convert to D3 nest map format
+   */
+  const toD3Map = (): D3NestMap<T> => {
+    const prop = childProp.value;
+    
+    const convert = (vals: GroupValue<T>[]): D3NestMap<T> => {
+      const result: D3NestMap<T> = {};
+      
+      vals.forEach(val => {
+        const key = String(val.value);
+        const children = val[prop] as GroupValue<T>[];
+        if (children && children.length > 0) {
+          result[key] = convert(children);
+        } else {
+          result[key] = [...val.records];
+        }
+      });
+      
+      return result;
+    };
+    
+    return convert(values.value);
+  };
+
+  /**
+   * Create root value wrapper
+   */
+  const asRootVal = (name: string = 'Root', dimName: string = 'root'): GroupValue<T> => {
+    const prop = childProp.value;
+    const group = groupRef.value;
+    
+    const rootVal: any = {
+      value: name,
+      rawValue: name,
+      dim: dimName,
+      depth: 0,
+      records: group.records as T[],
+      parent: null,
+      [prop]: values.value
+    };
+
+    // Update children to reference new root
+    values.value.forEach(v => {
+      v.parent = rootVal;
+      // Update all descendant depths
+      const updateDepth = (val: GroupValue<T>, increment: number) => {
+        val.depth += increment;
+        const children = val[prop] as GroupValue<T>[];
+        if (children) {
+          children.forEach(child => updateDepth(child, increment));
+        }
+      };
+      updateDepth(v, 1);
+    });
+
+    return rootVal;
+  };
+
+  /**
+   * Get summary string for debugging
+   */
+  const summary = (depth: number = 0): string => {
+    const group = groupRef.value;
+    const prop = childProp.value;
+    const indent = '    '.repeat(depth);
+    const dim = group.dim || 'unknown';
+    const vals = values.value.length;
+    const recs = group.records ? group.records.length : 0;
+
+    const lines = [`${indent}${String(dim)}, ${recs} recs (${depth}) ${vals} vals:`];
+    
+    values.value.forEach(val => {
+      const valRecs = val.records ? val.records.length : 0;
+      const valIndent = '    '.repeat(depth + 1);
+      lines.push(`${valIndent}${val.value}, ${valRecs} recs`);
+      
+      const children = val[prop] as GroupValue<T>[];
+      if (children && children.length > 0) {
+        lines.push(`${valIndent}has ${children.length} children`);
+      }
+    });
+
+    return lines.join('\n');
+  };
+
+  return {
+    values,
+    lookup,
+    lookupMany,
+    rawValues,
+    flattenTree,
+    leafNodes,
+    nodesAtLevel,
+    namePaths,
+    aggregates,
+    sort,
+    sortBy,
+    toD3Entries,
+    toD3Map,
+    asRootVal,
+    summary
+  };
+}
diff --git a/src/composables/useGroupSelection.js b/src/composables/useGroupSelection.js
new file mode 100644
index 0000000..39391bd
--- /dev/null
+++ b/src/composables/useGroupSelection.js
@@ -0,0 +1,218 @@
+/**
+ * Composable for managing selection state on groups
+ * Provides reactive selection without mutating the original data
+ */
+
+import { ref, computed } from 'vue';
+import _ from 'lodash';
+
+/**
+ * Group selection composable
+ * @param {Object} groupResult - Result from useGrouping
+ * @returns {Object} Selection state and methods
+ */
+export function useGroupSelection(groupResult) {
+  // Track selected values
+  const selectedValues = ref([]);
+  
+  // Track highlighted values (for hover, etc.)
+  const highlightedValues = ref([]);
+
+  /**
+   * Select a value
+   */
+  const selectValue = (value) => {
+    if (!selectedValues.value.includes(value)) {
+      selectedValues.value.push(value);
+    }
+  };
+
+  /**
+   * Deselect a value
+   */
+  const deselectValue = (value) => {
+    const index = selectedValues.value.indexOf(value);
+    if (index > -1) {
+      selectedValues.value.splice(index, 1);
+    }
+  };
+
+  /**
+   * Toggle value selection
+   */
+  const toggleValue = (value) => {
+    if (selectedValues.value.includes(value)) {
+      deselectValue(value);
+    } else {
+      selectValue(value);
+    }
+  };
+
+  /**
+   * Clear all selections
+   */
+  const clearSelection = () => {
+    selectedValues.value = [];
+  };
+
+  /**
+   * Select multiple values
+   */
+  const selectMany = (values) => {
+    values.forEach(v => selectValue(v));
+  };
+
+  /**
+   * Check if value is selected
+   */
+  const isSelected = (value) => {
+    return selectedValues.value.includes(value);
+  };
+
+  /**
+   * Get all records from selected values
+   */
+  const selectedRecords = computed(() => {
+    return _.chain(selectedValues.value)
+      .map('records')
+      .flatten()
+      .value();
+  });
+
+  /**
+   * Get count of selected values
+   */
+  const selectedCount = computed(() => {
+    return selectedValues.value.length;
+  });
+
+  /**
+   * Highlight a value (for hover effects, etc.)
+   */
+  const highlightValue = (value) => {
+    if (!highlightedValues.value.includes(value)) {
+      highlightedValues.value.push(value);
+    }
+  };
+
+  /**
+   * Remove highlight from value
+   */
+  const unhighlightValue = (value) => {
+    const index = highlightedValues.value.indexOf(value);
+    if (index > -1) {
+      highlightedValues.value.splice(index, 1);
+    }
+  };
+
+  /**
+   * Clear all highlights
+   */
+  const clearHighlights = () => {
+    highlightedValues.value = [];
+  };
+
+  /**
+   * Check if value is highlighted
+   */
+  const isHighlighted = (value) => {
+    return highlightedValues.value.includes(value);
+  };
+
+  /**
+   * Select by filter function
+   */
+  const selectByFilter = (filterFn) => {
+    if (!groupResult.value) return;
+    
+    const values = groupResult.value.values || [];
+    
+    // Flatten tree and filter
+    const flatValues = [];
+    const flatten = (vals) => {
+      vals.forEach(v => {
+        flatValues.push(v);
+        const childProp = groupResult.value.childProp || 'children';
+        if (v[childProp]) {
+          flatten(v[childProp]);
+        }
+      });
+    };
+    
+    flatten(values);
+    
+    const matching = flatValues.filter(filterFn);
+    selectMany(matching);
+  };
+
+  /**
+   * Select all leaf nodes
+   */
+  const selectLeafNodes = () => {
+    if (!groupResult.value) return;
+    
+    const childProp = groupResult.value.childProp || 'children';
+    const leaves = [];
+    
+    const findLeaves = (vals) => {
+      vals.forEach(v => {
+        if (!v[childProp] || v[childProp].length === 0) {
+          leaves.push(v);
+        } else {
+          findLeaves(v[childProp]);
+        }
+      });
+    };
+    
+    findLeaves(groupResult.value.values || []);
+    selectMany(leaves);
+  };
+
+  /**
+   * Select values at specific depth
+   */
+  const selectAtDepth = (depth) => {
+    selectByFilter(v => v.depth === depth);
+  };
+
+  /**
+   * Get selection state summary
+   */
+  const selectionSummary = computed(() => {
+    return {
+      count: selectedCount.value,
+      recordCount: selectedRecords.value.length,
+      values: selectedValues.value.map(v => v.value)
+    };
+  });
+
+  return {
+    // State
+    selectedValues,
+    highlightedValues,
+
+    // Selection methods
+    selectValue,
+    deselectValue,
+    toggleValue,
+    clearSelection,
+    selectMany,
+    isSelected,
+
+    // Computed
+    selectedRecords,
+    selectedCount,
+    selectionSummary,
+
+    // Highlight methods
+    highlightValue,
+    unhighlightValue,
+    clearHighlights,
+    isHighlighted,
+
+    // Advanced selection
+    selectByFilter,
+    selectLeafNodes,
+    selectAtDepth
+  };
+}
diff --git a/src/composables/useGroupSelection.ts b/src/composables/useGroupSelection.ts
new file mode 100644
index 0000000..b4511a0
--- /dev/null
+++ b/src/composables/useGroupSelection.ts
@@ -0,0 +1,227 @@
+/**
+ * Composable for managing selection state on groups
+ * Provides reactive selection without mutating the original data
+ */
+
+import { ref, computed, isRef, type Ref, type ComputedRef } from 'vue';
+import _ from 'lodash';
+import type { GroupResult, GroupValue, UseGroupSelectionReturn, SelectionSummary } from '../types';
+
+/**
+ * Group selection composable
+ * @param groupResult - Result from useGrouping
+ * @returns Selection state and methods
+ */
+export function useGroupSelection<T extends Record<string, any>>(
+  groupResult: GroupResult<T> | Ref<GroupResult<T>> | ComputedRef<GroupResult<T>>
+): UseGroupSelectionReturn<T> {
+  const groupRef = isRef(groupResult) ? groupResult : ref(groupResult);
+  
+  // Track selected values - use any to avoid Vue's unwrap issues
+  const selectedValues = ref<any[]>([]);
+  
+  // Track highlighted values (for hover, etc.)
+  const highlightedValues = ref<any[]>([]);
+
+  /**
+   * Select a value
+   */
+  const selectValue = (value: GroupValue<T>): void => {
+    if (!selectedValues.value.includes(value)) {
+      selectedValues.value.push(value);
+    }
+  };
+
+  /**
+   * Deselect a value
+   */
+  const deselectValue = (value: GroupValue<T>): void => {
+    const index = selectedValues.value.indexOf(value);
+    if (index > -1) {
+      selectedValues.value.splice(index, 1);
+    }
+  };
+
+  /**
+   * Toggle value selection
+   */
+  const toggleValue = (value: GroupValue<T>): void => {
+    if (selectedValues.value.includes(value)) {
+      deselectValue(value);
+    } else {
+      selectValue(value);
+    }
+  };
+
+  /**
+   * Clear all selections
+   */
+  const clearSelection = (): void => {
+    selectedValues.value = [];
+  };
+
+  /**
+   * Select multiple values
+   */
+  const selectMany = (values: GroupValue<T>[]): void => {
+    values.forEach(v => selectValue(v));
+  };
+
+  /**
+   * Check if value is selected
+   */
+  const isSelected = (value: GroupValue<T>): boolean => {
+    return selectedValues.value.includes(value);
+  };
+
+  /**
+   * Get all records from selected values
+   */
+  const selectedRecords: ComputedRef<T[]> = computed(() => {
+    return _.chain(selectedValues.value)
+      .map('records')
+      .flatten()
+      .value() as T[];
+  });
+
+  /**
+   * Get count of selected values
+   */
+  const selectedCount: ComputedRef<number> = computed(() => {
+    return selectedValues.value.length;
+  });
+
+  /**
+   * Highlight a value (for hover effects, etc.)
+   */
+  const highlightValue = (value: GroupValue<T>): void => {
+    if (!highlightedValues.value.includes(value)) {
+      highlightedValues.value.push(value);
+    }
+  };
+
+  /**
+   * Remove highlight from value
+   */
+  const unhighlightValue = (value: GroupValue<T>): void => {
+    const index = highlightedValues.value.indexOf(value);
+    if (index > -1) {
+      highlightedValues.value.splice(index, 1);
+    }
+  };
+
+  /**
+   * Clear all highlights
+   */
+  const clearHighlights = (): void => {
+    highlightedValues.value = [];
+  };
+
+  /**
+   * Check if value is highlighted
+   */
+  const isHighlighted = (value: GroupValue<T>): boolean => {
+    return highlightedValues.value.includes(value);
+  };
+
+  /**
+   * Select by filter function
+   */
+  const selectByFilter = (filterFn: (value: GroupValue<T>) => boolean): void => {
+    const group = groupRef.value;
+    if (!group) return;
+    
+    const values = group.values || [];
+    
+    // Flatten tree and filter
+    const flatValues: GroupValue<T>[] = [];
+    const flatten = (vals: any[]) => {
+      vals.forEach((v: any) => {
+        flatValues.push(v);
+        const childProp = group.childProp || 'children';
+        const children = v[childProp];
+        if (children) {
+          flatten(children);
+        }
+      });
+    };
+    
+    flatten(values);
+    
+    const matching = flatValues.filter(filterFn);
+    selectMany(matching);
+  };
+
+  /**
+   * Select all leaf nodes
+   */
+  const selectLeafNodes = (): void => {
+    const group = groupRef.value;
+    if (!group) return;
+    
+    const childProp = group.childProp || 'children';
+    const leaves: GroupValue<T>[] = [];
+    
+    const findLeaves = (vals: any[]) => {
+      vals.forEach((v: any) => {
+        const children = v[childProp];
+        if (!children || children.length === 0) {
+          leaves.push(v);
+        } else {
+          findLeaves(children);
+        }
+      });
+    };
+    
+    findLeaves(group.values || []);
+    selectMany(leaves);
+  };
+
+  /**
+   * Select values at specific depth
+   */
+  const selectAtDepth = (depth: number): void => {
+    selectByFilter(v => v.depth === depth);
+  };
+
+  /**
+   * Get selection state summary
+   */
+  const selectionSummary: ComputedRef<SelectionSummary> = computed(() => {
+    return {
+      count: selectedCount.value,
+      recordCount: selectedRecords.value.length,
+      values: selectedValues.value.map((v: any) => v.value)
+    };
+  });
+
+  return {
+    // State
+    selectedValues: selectedValues as Ref<GroupValue<T>[]>,
+    highlightedValues: highlightedValues as Ref<GroupValue<T>[]>,
+
+    // Selection methods
+    selectValue,
+    deselectValue,
+    toggleValue,
+    clearSelection,
+    selectMany,
+    isSelected,
+
+    // Computed
+    selectedRecords,
+    selectedCount,
+    selectionSummary,
+
+    // Highlight methods
+    highlightValue,
+    unhighlightValue,
+    clearHighlights,
+    isHighlighted,
+
+    // Advanced selection
+    selectByFilter,
+    selectLeafNodes,
+    selectAtDepth
+  };
+}
diff --git a/src/composables/useGroupValue.js b/src/composables/useGroupValue.js
new file mode 100644
index 0000000..f4ee210
--- /dev/null
+++ b/src/composables/useGroupValue.js
@@ -0,0 +1,200 @@
+/**
+ * Composable for working with individual group values
+ * Provides methods for paths, aggregates, and navigation
+ */
+
+import { computed, unref } from 'vue';
+import _ from 'lodash';
+import { createAggregator, calculatePct } from '../utils/groupHelpers.js';
+
+/**
+ * Group value composable
+ * @param {Object} value - Group value object
+ * @param {String} childProp - Property name for children (default: 'children')
+ * @returns {Object} Methods and computed properties for the value
+ */
+export function useGroupValue(value, childProp = 'children') {
+  const val = unref(value);
+
+  /**
+   * Get value's children
+   */
+  const children = computed(() => {
+    return val[childProp] || [];
+  });
+
+  /**
+   * Check if value has children
+   */
+  const hasChildren = computed(() => {
+    return children.value && children.value.length > 0;
+  });
+
+  /**
+   * Get all descendants (recursive)
+   */
+  const descendants = computed(() => {
+    if (!hasChildren.value) return [];
+    
+    const result = [];
+    const traverse = (vals) => {
+      vals.forEach(v => {
+        result.push(v);
+        if (v[childProp] && v[childProp].length > 0) {
+          traverse(v[childProp]);
+        }
+      });
+    };
+    
+    traverse(children.value);
+    return result;
+  });
+
+  /**
+   * Get leaf nodes (values with no children)
+   */
+  const leafNodes = computed(() => {
+    if (!hasChildren.value) return [val];
+    
+    return descendants.value.filter(v => 
+      !v[childProp] || v[childProp].length === 0
+    );
+  });
+
+  /**
+   * Get path from root to this value
+   */
+  const pedigree = computed(() => {
+    const path = [];
+    let ptr = val;
+    
+    path.push(ptr);
+    while (ptr.parent) {
+      ptr = ptr.parent;
+      path.unshift(ptr);
+    }
+    
+    return path;
+  });
+
+  /**
+   * Get name path (string representation)
+   */
+  const namePath = (opts = {}) => {
+    const delim = opts.delim || '/';
+    const path = pedigree.value.map(v => v.value);
+    
+    if (opts.noRoot) path.shift();
+    if (opts.backwards) path.reverse();
+    
+    return opts.asArray ? path : path.join(delim);
+  };
+
+  /**
+   * Get dimension path
+   */
+  const dimPath = (opts = {}) => {
+    const delim = opts.delim || '/';
+    const path = pedigree.value.map(v => v.dim);
+    
+    if (opts.noRoot) path.shift();
+    if (opts.backwards) path.reverse();
+    
+    return opts.asArray ? path : path.join(delim);
+  };
+
+  /**
+   * Calculate aggregate on records
+   */
+  const aggregate = (func, field) => {
+    return createAggregator(val.records, func, field);
+  };
+
+  /**
+   * Get percentage of parent
+   */
+  const pct = computed(() => {
+    if (!val.parent || !val.parent.records) return 1;
+    return calculatePct(val.records, val.parent.records);
+  });
+
+  /**
+   * Get previous sibling
+   */
+  const previous = () => {
+    if (!val.parent || !val.parent[childProp]) return null;
+    
+    const siblings = val.parent[childProp];
+    const index = siblings.indexOf(val);
+    
+    return index > 0 ? siblings[index - 1] : null;
+  };
+
+  /**
+   * Get next sibling
+   */
+  const next = () => {
+    if (!val.parent || !val.parent[childProp]) return null;
+    
+    const siblings = val.parent[childProp];
+    const index = siblings.indexOf(val);
+    
+    return index < siblings.length - 1 ? siblings[index + 1] : null;
+  };
+
+  /**
+   * Lookup child by value or path
+   */
+  const lookup = (query) => {
+    if (!hasChildren.value) {
+      throw new Error("Cannot lookup on value without children");
+    }
+
+    if (Array.isArray(query)) {
+      // Path lookup
+      if (val.value == query[0]) {
+        query = query.slice(1);
+        if (query.length === 0) return val;
+      }
+      
+      let result = children.value.find(c => c.value == query[0]);
+      for (let i = 1; i < query.length && result; i++) {
+        const childVals = result[childProp];
+        if (!childVals) break;
+        result = childVals.find(c => c.value == query[i]);
+      }
+      return result;
+    } else {
+      // Single value lookup
+      return children.value.find(c => c.value == query);
+    }
+  };
+
+  /**
+   * Get root list
+   */
+  const rootValue = computed(() => {
+    let ptr = val;
+    while (ptr.parent) {
+      ptr = ptr.parent;
+    }
+    return ptr;
+  });
+
+  return {
+    value: val,
+    children,
+    hasChildren,
+    descendants,
+    leafNodes,
+    pedigree,
+    namePath,
+    dimPath,
+    aggregate,
+    pct,
+    previous,
+    next,
+    lookup,
+    rootValue
+  };
+}
diff --git a/src/composables/useGroupValue.ts b/src/composables/useGroupValue.ts
new file mode 100644
index 0000000..0b227b5
--- /dev/null
+++ b/src/composables/useGroupValue.ts
@@ -0,0 +1,213 @@
+/**
+ * Composable for working with individual group values
+ * Provides methods for paths, aggregates, and navigation
+ */
+
+import { computed, type ComputedRef } from 'vue';
+import _ from 'lodash';
+import { createAggregator, calculatePct } from '../utils/groupHelpers';
+import type { GroupValue, PathOptions, UseGroupValueReturn } from '../types';
+
+/**
+ * Group value composable
+ * @param value - Group value object
+ * @param childProp - Property name for children (default: 'children')
+ * @returns Methods and computed properties for the value
+ */
+export function useGroupValue<T extends Record<string, any>>(
+  value: GroupValue<T>,
+  childProp: string = 'children'
+): UseGroupValueReturn<T> {
+  const val = value;
+
+  /**
+   * Get value's children
+   */
+  const children: ComputedRef<GroupValue<T>[]> = computed(() => {
+    return (val[childProp] as GroupValue<T>[]) || [];
+  });
+
+  /**
+   * Check if value has children
+   */
+  const hasChildren: ComputedRef<boolean> = computed(() => {
+    return children.value && children.value.length > 0;
+  });
+
+  /**
+   * Get all descendants (recursive)
+   */
+  const descendants: ComputedRef<GroupValue<T>[]> = computed(() => {
+    if (!hasChildren.value) return [];
+    
+    const result: GroupValue<T>[] = [];
+    const traverse = (vals: GroupValue<T>[]) => {
+      vals.forEach(v => {
+        result.push(v);
+        const kids = v[childProp] as GroupValue<T>[];
+        if (kids && kids.length > 0) {
+          traverse(kids);
+        }
+      });
+    };
+    
+    traverse(children.value);
+    return result;
+  });
+
+  /**
+   * Get leaf nodes (values with no children)
+   */
+  const leafNodes: ComputedRef<GroupValue<T>[]> = computed(() => {
+    if (!hasChildren.value) return [val];
+    
+    return descendants.value.filter(v => {
+      const kids = v[childProp] as GroupValue<T>[];
+      return !kids || kids.length === 0;
+    });
+  });
+
+  /**
+   * Get path from root to this value
+   */
+  const pedigree: ComputedRef<GroupValue<T>[]> = computed(() => {
+    const path: GroupValue<T>[] = [];
+    let ptr: GroupValue<T> | null = val;
+    
+    path.push(ptr);
+    while (ptr.parent) {
+      ptr = ptr.parent;
+      path.unshift(ptr);
+    }
+    
+    return path;
+  });
+
+  /**
+   * Get name path (string representation)
+   */
+  const namePath = (opts: PathOptions = {}): string | (string | number)[] => {
+    const delim = opts.delim || '/';
+    const path = pedigree.value.map(v => v.value);
+    
+    if (opts.noRoot) path.shift();
+    if (opts.backwards) path.reverse();
+    
+    return opts.asArray ? path : path.join(delim);
+  };
+
+  /**
+   * Get dimension path
+   */
+  const dimPath = (opts: PathOptions = {}): string | string[] => {
+    const delim = opts.delim || '/';
+    const path = pedigree.value.map(v => String(v.dim));
+    
+    if (opts.noRoot) path.shift();
+    if (opts.backwards) path.reverse();
+    
+    return opts.asArray ? path : path.join(delim);
+  };
+
+  /**
+   * Calculate aggregate on records
+   */
+  const aggregate = <R>(
+    func: (values: any[]) => R,
+    field?: keyof T | ((record: T) => any)
+  ): R => {
+    return createAggregator(val.records, func, field);
+  };
+
+  /**
+   * Get percentage of parent
+   */
+  const pct: ComputedRef<number> = computed(() => {
+    if (!val.parent || !val.parent.records) return 1;
+    return calculatePct(val.records, val.parent.records);
+  });
+
+  /**
+   * Get previous sibling
+   */
+  const previous = (): GroupValue<T> | null => {
+    if (!val.parent) return null;
+    
+    const siblings = val.parent[childProp] as GroupValue<T>[];
+    if (!siblings) return null;
+    
+    const index = siblings.indexOf(val);
+    return index > 0 ? siblings[index - 1] : null;
+  };
+
+  /**
+   * Get next sibling
+   */
+  const next = (): GroupValue<T> | null => {
+    if (!val.parent) return null;
+    
+    const siblings = val.parent[childProp] as GroupValue<T>[];
+    if (!siblings) return null;
+    
+    const index = siblings.indexOf(val);
+    return index < siblings.length - 1 ? siblings[index + 1] : null;
+  };
+
+  /**
+   * Lookup child by value or path
+   */
+  const lookup = (query: string | number | (string | number)[]): GroupValue<T> | undefined => {
+    if (!hasChildren.value) {
+      throw new Error("Cannot lookup on value without children");
+    }
+
+    if (Array.isArray(query)) {
+      // Path lookup
+      if (val.value == query[0]) {
+        const newQuery = query.slice(1);
+        if (newQuery.length === 0) return val;
+        query = newQuery;
+      }
+      
+      const queryArray = query as (string | number)[];
+      let result = children.value.find(c => c.value == queryArray[0]);
+      for (let i = 1; i < queryArray.length && result; i++) {
+        const childVals = result[childProp] as GroupValue<T>[];
+        if (!childVals) break;
+        result = childVals.find(c => c.value == queryArray[i]);
+      }
+      return result;
+    } else {
+      // Single value lookup
+      return children.value.find(c => c.value == query);
+    }
+  };
+
+  /**
+   * Get root value
+   */
+  const rootValue: ComputedRef<GroupValue<T>> = computed(() => {
+    let ptr = val;
+    while (ptr.parent) {
+      ptr = ptr.parent;
+    }
+    return ptr;
+  });
+
+  return {
+    value: val,
+    children,
+    hasChildren,
+    descendants,
+    leafNodes,
+    pedigree,
+    namePath,
+    dimPath,
+    aggregate,
+    pct,
+    previous,
+    next,
+    lookup,
+    rootValue
+  };
+}
diff --git a/src/composables/useGrouping.js b/src/composables/useGrouping.js
new file mode 100644
index 0000000..0de9c92
--- /dev/null
+++ b/src/composables/useGrouping.js
@@ -0,0 +1,236 @@
+/**
+ * Core grouping composable for Vue.js applications
+ * Provides reactive grouping functionality
+ */
+
+import { ref, computed, unref, toValue, isRef } from 'vue';
+import _ from 'lodash';
+import { 
+  isNumericGroup, 
+  filterOutEmpty, 
+  multiValuedGroupBy 
+} from '../utils/groupHelpers.js';
+
+/**
+ * Main grouping composable
+ * @param {Array|Ref<Array>} records - Records to group (can be reactive)
+ * @param {String|Function|Array|Ref} dimensions - Single dimension or array for multi-level
+ * @param {Object} options - Grouping options
+ * @returns {Object} Reactive grouping result with helper methods
+ */
+export function useGrouping(records, dimensions, options = {}) {
+  // Keep reactivity by checking if already a ref
+  const recordsRef = isRef(records) ? records : ref(records);
+  const dimensionsRef = isRef(dimensions) ? dimensions : ref(dimensions);
+  const optionsRef = isRef(options) ? options : ref(options);
+
+  /**
+   * Core grouping logic for single dimension
+   */
+  const groupByDimension = (recs, dim, opts) => {
+    const childProp = opts.childProp || 'children';
+    
+    // Clone records with index tracking
+    const clonedRecs = recs.map((rec, i) => ({
+      ...rec,
+      _recIdx: i
+    }));
+
+    // Apply pre-processing hook if provided
+    const processedRecs = opts.preListRecsHook ? 
+      opts.preListRecsHook(clonedRecs) : clonedRecs;
+
+    // Perform grouping
+    let groups;
+    if (opts.multiValuedGroup) {
+      const dimFunc = typeof dim === 'function' ? dim : d => d[dim];
+      const arrayDim = val => {
+        const retVal = dimFunc(val);
+        return Array.isArray(retVal) ? retVal : [retVal];
+      };
+      groups = multiValuedGroupBy(processedRecs, arrayDim);
+    } else {
+      if (opts.truncateBranchOnEmptyVal) {
+        const filtered = filterOutEmpty(processedRecs, dim);
+        groups = _.groupBy(filtered, dim);
+      } else {
+        groups = _.groupBy(processedRecs, dim);
+      }
+    }
+
+    // Exclude specific values if specified
+    if (opts.excludeValues) {
+      opts.excludeValues.forEach(val => {
+        delete groups[val];
+      });
+    }
+
+    // Determine if group is numeric
+    const isNumeric = _.has(opts, 'isNumeric') ? 
+      opts.isNumeric : isNumericGroup(groups);
+
+    // Create group values
+    const groupValues = _.map(_.toPairs(groups), ([key, groupRecs], i) => {
+      const value = {
+        value: isNumeric ? Number(key) : String(key),
+        rawValue: key,
+        records: groupRecs,
+        dim: opts.dimName || dim,
+        depth: opts.parent ? (opts.parent.depth + 1) : 0,
+        parent: opts.parent || null,
+        [childProp]: null
+      };
+
+      return value;
+    });
+
+    // Create list metadata
+    const result = {
+      values: groupValues,
+      records: clonedRecs,
+      dim: opts.dimName || dim,
+      isNumeric,
+      childProp
+    };
+
+    return result;
+  };
+
+  /**
+   * Multi-level grouping
+   */
+  const groupByMultipleDimensions = (recs, dims, opts) => {
+    let currentGroup = groupByDimension(recs, dims[0], opts);
+    
+    // Add subsequent levels
+    for (let i = 1; i < dims.length; i++) {
+      const dim = dims[i];
+      currentGroup.values.forEach(val => {
+        const childGroup = groupByDimension(
+          val.records, 
+          dim, 
+          { ...opts, parent: val }
+        );
+        val[currentGroup.childProp] = childGroup.values;
+      });
+    }
+    
+    return currentGroup;
+  };
+
+  /**
+   * Computed grouped result
+   */
+  const grouped = computed(() => {
+    const recs = toValue(recordsRef);
+    const dims = toValue(dimensionsRef);
+    const opts = toValue(optionsRef);
+
+    if (!recs || recs.length === 0) {
+      return {
+        values: [],
+        records: [],
+        dim: null,
+        isNumeric: false,
+        childProp: opts.childProp || 'children'
+      };
+    }
+
+    if (Array.isArray(dims)) {
+      return groupByMultipleDimensions(recs, dims, opts);
+    } else {
+      return groupByDimension(recs, dims, opts);
+    }
+  });
+
+  /**
+   * Helper methods
+   */
+  const methods = {
+    // Get all values as plain array
+    rawValues: computed(() => 
+      grouped.value.values.map(v => v.value)
+    ),
+
+    // Get all records
+    allRecords: computed(() => grouped.value.records),
+
+    // Lookup a value
+    lookup: (query) => {
+      const values = grouped.value.values;
+      
+      if (Array.isArray(query)) {
+        // Path lookup for hierarchical groups
+        let result = values.find(v => v.value == query[0]);
+        for (let i = 1; i < query.length && result; i++) {
+          const children = result[grouped.value.childProp];
+          if (!children) break;
+          result = children.find(v => v.value == query[i]);
+        }
+        return result;
+      } else {
+        // Single value lookup
+        return values.find(v => v.value == query);
+      }
+    },
+
+    // Add another level of grouping
+    addLevel: (newDim, newOpts = {}) => {
+      const current = grouped.value;
+      const childProp = current.childProp;
+      
+      current.values.forEach(val => {
+        if (!val[childProp]) {
+          const childGroup = groupByDimension(
+            val.records,
+            newDim,
+            { ...newOpts, parent: val }
+          );
+          val[childProp] = childGroup.values;
+        }
+      });
+    },
+
+    // Get leaf nodes
+    leafNodes: computed(() => {
+      const childProp = grouped.value.childProp;
+      const leaves = [];
+      
+      const findLeaves = (values) => {
+        values.forEach(val => {
+          if (!val[childProp] || val[childProp].length === 0) {
+            leaves.push(val);
+          } else {
+            findLeaves(val[childProp]);
+          }
+        });
+      };
+      
+      findLeaves(grouped.value.values);
+      return leaves;
+    }),
+
+    // Flatten entire tree
+    flattenTree: computed(() => {
+      const childProp = grouped.value.childProp;
+      const flat = [];
+      
+      const flatten = (values) => {
+        values.forEach(val => {
+          flat.push(val);
+          if (val[childProp] && val[childProp].length > 0) {
+            flatten(val[childProp]);
+          }
+        });
+      };
+      
+      flatten(grouped.value.values);
+      return flat;
+    })
+  };
+
+  return {
+    grouped,
+    ...methods
+  };
+}
diff --git a/src/composables/useGrouping.ts b/src/composables/useGrouping.ts
new file mode 100644
index 0000000..d22dcba
--- /dev/null
+++ b/src/composables/useGrouping.ts
@@ -0,0 +1,257 @@
+/**
+ * Core grouping composable for Vue.js applications
+ * Provides reactive grouping functionality
+ */
+
+import { ref, computed, isRef, type Ref, type ComputedRef } from 'vue';
+import _ from 'lodash';
+import { 
+  isNumericGroup, 
+  filterOutEmpty, 
+  multiValuedGroupBy 
+} from '../utils/groupHelpers';
+import type {
+  GroupingOptions,
+  GroupValue,
+  GroupResult,
+  Dimension,
+  UseGroupingReturn
+} from '../types';
+
+/**
+ * Main grouping composable
+ * @param records - Records to group (can be reactive)
+ * @param dimensions - Single dimension or array for multi-level
+ * @param options - Grouping options
+ * @returns Reactive grouping result with helper methods
+ */
+export function useGrouping<T extends Record<string, any>>(
+  records: T[] | Ref<T[]>,
+  dimensions: Dimension<T> | Ref<Dimension<T>>,
+  options: GroupingOptions | Ref<GroupingOptions> = {}
+): UseGroupingReturn<T> {
+  // Keep reactivity by checking if already a ref
+  const recordsRef = isRef(records) ? records : ref(records);
+  const dimensionsRef = isRef(dimensions) ? dimensions : ref(dimensions);
+  const optionsRef = isRef(options) ? options : ref(options);
+
+  /**
+   * Core grouping logic for single dimension
+   */
+  const groupByDimension = (
+    recs: T[],
+    dim: keyof T | ((record: T) => string | number),
+    opts: GroupingOptions
+  ): GroupResult<T> => {
+    const childProp = opts.childProp || 'children';
+    
+    // Clone records with index tracking
+    const clonedRecs = recs.map((rec, i) => ({
+      ...rec,
+      _recIdx: i
+    }));
+
+    // Apply pre-processing hook if provided
+    const processedRecs = opts.preListRecsHook ? 
+      opts.preListRecsHook(clonedRecs) : clonedRecs;
+
+    // Perform grouping
+    let groups: Record<string, T[]>;
+    if (opts.multiValuedGroup) {
+      const dimFunc = typeof dim === 'function' ? dim : (d: T) => d[dim as keyof T];
+      const arrayDim = (val: T): (string | number)[] => {
+        const retVal = dimFunc(val);
+        return Array.isArray(retVal) ? retVal : [retVal];
+      };
+      groups = multiValuedGroupBy(processedRecs, arrayDim);
+    } else {
+      if (opts.truncateBranchOnEmptyVal) {
+        const filtered = filterOutEmpty(processedRecs, dim);
+        groups = _.groupBy(filtered, dim as any);
+      } else {
+        groups = _.groupBy(processedRecs, dim as any);
+      }
+    }
+
+    // Exclude specific values if specified
+    if (opts.excludeValues) {
+      opts.excludeValues.forEach(val => {
+        delete groups[String(val)];
+      });
+    }
+
+    // Determine if group is numeric
+    const isNumeric = _.has(opts, 'isNumeric') ? 
+      opts.isNumeric! : isNumericGroup(groups);
+
+    // Create group values
+    const groupValues: GroupValue<T>[] = _.map(_.toPairs(groups), ([key, groupRecs]) => {
+      const value: GroupValue<T> = {
+        value: isNumeric ? Number(key) : String(key),
+        rawValue: key,
+        records: groupRecs,
+        dim: opts.dimName || dim,
+        depth: opts.parent ? (opts.parent.depth + 1) : 0,
+        parent: opts.parent || null,
+        [childProp]: null
+      };
+
+      return value;
+    });
+
+    // Create list metadata
+    const result: GroupResult<T> = {
+      values: groupValues,
+      records: clonedRecs,
+      dim: opts.dimName || dim,
+      isNumeric,
+      childProp
+    };
+
+    return result;
+  };
+
+  /**
+   * Multi-level grouping
+   */
+  const groupByMultipleDimensions = (
+    recs: T[],
+    dims: (keyof T | ((record: T) => string | number))[],
+    opts: GroupingOptions
+  ): GroupResult<T> => {
+    let currentGroup = groupByDimension(recs, dims[0], opts);
+    
+    // Add subsequent levels
+    for (let i = 1; i < dims.length; i++) {
+      const dim = dims[i];
+      currentGroup.values.forEach(val => {
+        const childGroup = groupByDimension(
+          val.records, 
+          dim, 
+          { ...opts, parent: val }
+        );
+        val[currentGroup.childProp] = childGroup.values;
+      });
+    }
+    
+    return currentGroup;
+  };
+
+  /**
+   * Computed grouped result
+   */
+  const grouped: ComputedRef<GroupResult<T>> = computed(() => {
+    const recs = recordsRef.value as T[];
+    const dims = dimensionsRef.value;
+    const opts = optionsRef.value;
+
+    if (!recs || recs.length === 0) {
+      return {
+        values: [],
+        records: [],
+        dim: null as any,
+        isNumeric: false,
+        childProp: opts.childProp || 'children'
+      };
+    }
+
+    if (Array.isArray(dims)) {
+      return groupByMultipleDimensions(recs, dims, opts);
+    } else {
+      return groupByDimension(recs, dims, opts);
+    }
+  });
+
+  /**
+   * Helper methods
+   */
+  const methods = {
+    // Get all values as plain array
+    rawValues: computed(() => 
+      grouped.value.values.map(v => v.value)
+    ),
+
+    // Get all records
+    allRecords: computed(() => grouped.value.records),
+
+    // Lookup a value
+    lookup: (query: string | number | (string | number)[]): GroupValue<T> | undefined => {
+      const values = grouped.value.values;
+      
+      if (Array.isArray(query)) {
+        // Path lookup for hierarchical groups
+        let result = values.find(v => v.value == query[0]);
+        for (let i = 1; i < query.length && result; i++) {
+          const children = result[grouped.value.childProp] as GroupValue<T>[];
+          if (!children) break;
+          result = children.find(v => v.value == query[i]);
+        }
+        return result;
+      } else {
+        // Single value lookup
+        return values.find(v => v.value == query);
+      }
+    },
+
+    // Add another level of grouping
+    addLevel: (newDim: Dimension<T>, newOpts: GroupingOptions = {}): void => {
+      const current = grouped.value;
+      const childProp = current.childProp;
+      
+      current.values.forEach(val => {
+        if (!val[childProp]) {
+          const childGroup = groupByDimension(
+            val.records,
+            newDim as any,
+            { ...newOpts, parent: val }
+          );
+          val[childProp] = childGroup.values;
+        }
+      });
+    },
+
+    // Get leaf nodes
+    leafNodes: computed(() => {
+      const childProp = grouped.value.childProp;
+      const leaves: GroupValue<T>[] = [];
+      
+      const findLeaves = (values: GroupValue<T>[]) => {
+        values.forEach(val => {
+          const children = val[childProp] as GroupValue<T>[];
+          if (!children || children.length === 0) {
+            leaves.push(val);
+          } else {
+            findLeaves(children);
+          }
+        });
+      };
+      
+      findLeaves(grouped.value.values);
+      return leaves;
+    }),
+
+    // Flatten entire tree
+    flattenTree: computed(() => {
+      const childProp = grouped.value.childProp;
+      const flat: GroupValue<T>[] = [];
+      
+      const flatten = (values: GroupValue<T>[]) => {
+        values.forEach(val => {
+          flat.push(val);
+          const children = val[childProp] as GroupValue<T>[];
+          if (children && children.length > 0) {
+            flatten(children);
+          }
+        });
+      };
+      
+      flatten(grouped.value.values);
+      return flat;
+    })
+  };
+
+  return {
+    grouped,
+    ...methods
+  };
+}
diff --git a/src/index.js b/src/index.js
new file mode 100644
index 0000000..ccdd8e6
--- /dev/null
+++ b/src/index.js
@@ -0,0 +1,60 @@
+/**
+ * Supergroup Vue Composables
+ * 
+ * A modular, reactive grouping utility for Vue.js applications
+ * 
+ * @example
+ * import { useGrouping, useGroupList } from 'supergroup/composables'
+ * 
+ * const data = ref([...])
+ * const grouping = useGrouping(data, ['category', 'subcategory'])
+ * const list = useGroupList(grouping.grouped)
+ */
+
+import { useGrouping } from './composables/useGrouping.js';
+import { useGroupValue } from './composables/useGroupValue.js';
+import { useGroupList } from './composables/useGroupList.js';
+import { useGroupSelection } from './composables/useGroupSelection.js';
+
+import {
+  isNumericGroup,
+  filterOutEmpty,
+  createDimPath,
+  createAggregator,
+  calculatePct,
+  multiValuedGroupBy,
+  findRootNodes
+} from './utils/groupHelpers.js';
+
+export {
+  useGrouping,
+  useGroupValue,
+  useGroupList,
+  useGroupSelection,
+  isNumericGroup,
+  filterOutEmpty,
+  createDimPath,
+  createAggregator,
+  calculatePct,
+  multiValuedGroupBy,
+  findRootNodes
+};
+
+/**
+ * Convenience function for quick grouping without Vue composable
+ * Useful for non-reactive contexts or server-side use
+ */
+export function supergroup(records, dimensions, options = {}) {
+  // Non-reactive version - just returns the grouped data
+  // Create a temporary ref-like wrapper
+  const recordsRef = { value: records };
+  const dimensionsRef = { value: dimensions };
+  const optionsRef = { value: options };
+  
+  // Use the grouping composable
+  const grouping = useGrouping(recordsRef, dimensionsRef, optionsRef);
+  
+  // Return just the grouped value, not reactive
+  return grouping.grouped.value;
+}
+
diff --git a/src/index.ts b/src/index.ts
new file mode 100644
index 0000000..115b742
--- /dev/null
+++ b/src/index.ts
@@ -0,0 +1,85 @@
+/**
+ * Supergroup Vue Composables
+ * 
+ * A modular, reactive grouping utility for Vue.js applications
+ * 
+ * @example
+ * import { ref } from 'vue';
+ * import { useGrouping, useGroupList } from 'supergroup/composables';
+ * 
+ * const data = ref<MyRecord[]>([...]);
+ * const grouping = useGrouping(data, ['category', 'subcategory']);
+ * const list = useGroupList(grouping.grouped);
+ */
+
+import { useGrouping } from './composables/useGrouping';
+import { useGroupValue } from './composables/useGroupValue';
+import { useGroupList } from './composables/useGroupList';
+import { useGroupSelection } from './composables/useGroupSelection';
+
+import {
+  isNumericGroup,
+  filterOutEmpty,
+  createDimPath,
+  createAggregator,
+  calculatePct,
+  multiValuedGroupBy,
+  findRootNodes
+} from './utils/groupHelpers';
+
+// Export all composables
+export {
+  useGrouping,
+  useGroupValue,
+  useGroupList,
+  useGroupSelection
+};
+
+// Export utility functions
+export {
+  isNumericGroup,
+  filterOutEmpty,
+  createDimPath,
+  createAggregator,
+  calculatePct,
+  multiValuedGroupBy,
+  findRootNodes
+};
+
+// Export types
+export type {
+  PathOptions,
+  GroupingOptions,
+  Dimension,
+  GroupValue,
+  GroupResult,
+  UseGroupingReturn,
+  UseGroupValueReturn,
+  UseGroupListReturn,
+  UseGroupSelectionReturn,
+  D3NestEntry,
+  D3NestMap,
+  SelectionSummary
+} from './types';
+
+/**
+ * Convenience function for quick grouping without Vue composable
+ * Useful for non-reactive contexts or server-side use
+ */
+export function supergroup<T extends Record<string, any>>(
+  records: T[],
+  dimensions: import('./types').Dimension<T>,
+  options: import('./types').GroupingOptions = {}
+): import('./types').GroupResult<T> {
+  // Non-reactive version - just returns the grouped data
+  // Create a temporary ref-like wrapper
+  const recordsRef = { value: records };
+  const dimensionsRef = { value: dimensions };
+  const optionsRef = { value: options };
+  
+  // Use the grouping composable
+  const grouping = useGrouping(recordsRef as any, dimensionsRef as any, optionsRef as any);
+  
+  // Return just the grouped value, not reactive
+  return grouping.grouped.value as import('./types').GroupResult<T>;
+}
diff --git a/src/types.ts b/src/types.ts
new file mode 100644
index 0000000..bb3a250
--- /dev/null
+++ b/src/types.ts
@@ -0,0 +1,162 @@
+/**
+ * Core type definitions for supergroup
+ */
+
+import { Ref, ComputedRef } from 'vue';
+
+/**
+ * Options for path formatting
+ */
+export interface PathOptions {
+  delim?: string;
+  dimName?: boolean;
+  noRoot?: boolean;
+  backwards?: boolean;
+  asArray?: boolean;
+}
+
+/**
+ * Options for grouping
+ */
+export interface GroupingOptions {
+  childProp?: string;
+  excludeValues?: (string | number)[];
+  dimName?: string;
+  truncateBranchOnEmptyVal?: boolean;
+  multiValuedGroup?: boolean;
+  preListRecsHook?: <T>(records: T[]) => T[];
+  isNumeric?: boolean;
+  parent?: GroupValue<any>;
+}
+
+/**
+ * Dimension type - can be a property key, function, or array of dimensions
+ */
+export type Dimension<T> = keyof T | ((record: T) => string | number) | Array<keyof T | ((record: T) => string | number)>;
+
+/**
+ * A group value with records and metadata
+ */
+export interface GroupValue<T> {
+  value: string | number;
+  rawValue: string;
+  records: T[];
+  dim: string | Dimension<T>;
+  depth: number;
+  parent: GroupValue<T> | null;
+  children?: GroupValue<T>[];
+  [key: string]: any;
+}
+
+/**
+ * Result of grouping operation
+ */
+export interface GroupResult<T> {
+  values: GroupValue<T>[];
+  records: T[];
+  dim: string | Dimension<T>;
+  isNumeric: boolean;
+  childProp: string;
+}
+
+/**
+ * Return type from useGrouping composable
+ */
+export interface UseGroupingReturn<T> {
+  grouped: ComputedRef<GroupResult<T>>;
+  rawValues: ComputedRef<(string | number)[]>;
+  allRecords: ComputedRef<T[]>;
+  lookup: (query: string | number | (string | number)[]) => GroupValue<T> | undefined;
+  addLevel: (newDim: Dimension<T>, newOpts?: GroupingOptions) => void;
+  leafNodes: ComputedRef<GroupValue<T>[]>;
+  flattenTree: ComputedRef<GroupValue<T>[]>;
+}
+
+/**
+ * Return type from useGroupValue composable
+ */
+export interface UseGroupValueReturn<T> {
+  value: GroupValue<T>;
+  children: ComputedRef<GroupValue<T>[]>;
+  hasChildren: ComputedRef<boolean>;
+  descendants: ComputedRef<GroupValue<T>[]>;
+  leafNodes: ComputedRef<GroupValue<T>[]>;
+  pedigree: ComputedRef<GroupValue<T>[]>;
+  namePath: (opts?: PathOptions) => string | (string | number)[];
+  dimPath: (opts?: PathOptions) => string | string[];
+  aggregate: <R>(func: (values: any[]) => R, field?: keyof T | ((record: T) => any)) => R;
+  pct: ComputedRef<number>;
+  previous: () => GroupValue<T> | null;
+  next: () => GroupValue<T> | null;
+  lookup: (query: string | number | (string | number)[]) => GroupValue<T> | undefined;
+  rootValue: ComputedRef<GroupValue<T>>;
+}
+
+/**
+ * D3 nest entry format
+ */
+export interface D3NestEntry<T> {
+  key: string;
+  values: D3NestEntry<T>[] | T[];
+}
+
+/**
+ * D3 nest map format
+ */
+export type D3NestMap<T> = {
+  [key: string]: D3NestMap<T> | T[];
+};
+
+/**
+ * Return type from useGroupList composable
+ */
+export interface UseGroupListReturn<T> {
+  values: ComputedRef<GroupValue<T>[]>;
+  lookup: (query: string | number | (string | number)[]) => GroupValue<T> | undefined;
+  lookupMany: (queries: (string | number)[]) => GroupValue<T>[];
+  rawValues: ComputedRef<(string | number)[]>;
+  flattenTree: ComputedRef<GroupValue<T>[]>;
+  leafNodes: ComputedRef<GroupValue<T>[]>;
+  nodesAtLevel: (level: number) => GroupValue<T>[];
+  namePaths: (opts?: PathOptions) => string[];
+  aggregates: <R>(func: (values: any[]) => R, field?: keyof T | ((record: T) => any), returnType?: 'array' | 'dict') => R[] | Record<string | number, R>;
+  sort: (compareFn: (a: GroupValue<T>, b: GroupValue<T>) => number) => GroupValue<T>[];
+  sortBy: (iteratee: ((value: GroupValue<T>) => any) | keyof GroupValue<T>) => GroupValue<T>[];
+  toD3Entries: () => D3NestEntry<T>[];
+  toD3Map: () => D3NestMap<T>;
+  asRootVal: (name?: string, dimName?: string) => GroupValue<T>;
+  summary: (depth?: number) => string;
+}
+
+/**
+ * Selection summary
+ */
+export interface SelectionSummary {
+  count: number;
+  recordCount: number;
+  values: (string | number)[];
+}
+
+/**
+ * Return type from useGroupSelection composable
+ */
+export interface UseGroupSelectionReturn<T> {
+  selectedValues: Ref<GroupValue<T>[]>;
+  highlightedValues: Ref<GroupValue<T>[]>;
+  selectValue: (value: GroupValue<T>) => void;
+  deselectValue: (value: GroupValue<T>) => void;
+  toggleValue: (value: GroupValue<T>) => void;
+  clearSelection: () => void;
+  selectMany: (values: GroupValue<T>[]) => void;
+  isSelected: (value: GroupValue<T>) => boolean;
+  selectedRecords: ComputedRef<T[]>;
+  selectedCount: ComputedRef<number>;
+  selectionSummary: ComputedRef<SelectionSummary>;
+  highlightValue: (value: GroupValue<T>) => void;
+  unhighlightValue: (value: GroupValue<T>) => void;
+  clearHighlights: () => void;
+  isHighlighted: (value: GroupValue<T>) => boolean;
+  selectByFilter: (filterFn: (value: GroupValue<T>) => boolean) => void;
+  selectLeafNodes: () => void;
+  selectAtDepth: (depth: number) => void;
+}
diff --git a/src/utils/groupHelpers.js b/src/utils/groupHelpers.js
new file mode 100644
index 0000000..714a641
--- /dev/null
+++ b/src/utils/groupHelpers.js
@@ -0,0 +1,104 @@
+/**
+ * Core helper utilities for grouping operations
+ * These are pure functions without Vue dependencies
+ */
+
+import _ from 'lodash';
+
+/**
+ * Check if entire group list is numeric
+ */
+export function isNumericGroup(groups) {
+  return _.every(_.keys(groups), (k) => {
+    return k === null ||
+           k === undefined ||
+           (!isNaN(Number(k))) ||
+           ["null", ".", "undefined"].indexOf(k.toLowerCase()) > -1;
+  });
+}
+
+/**
+ * Filter out empty values from records
+ */
+export function filterOutEmpty(recs, dim) {
+  const func = _.isFunction(dim) ? dim : d => d[dim];
+  return recs.filter(r => 
+    !_.isEmpty(func(r)) || 
+    (_.isNumber(func(r)) && isFinite(func(r)))
+  );
+}
+
+/**
+ * Create dimension path string
+ */
+export function createDimPath(val, opts = {}) {
+  const delim = opts.delim || '/';
+  const path = [];
+  let ptr = val;
+  
+  path.push(val);
+  while ((ptr = ptr.parent)) {
+    path.unshift(ptr);
+  }
+  
+  if (opts.noRoot) path.shift();
+  if (opts.backwards) path.reverse();
+  
+  return opts.dimName ? 
+    path.map(v => v.dim).join(delim) :
+    path.map(v => String(v.value || v)).join(delim);
+}
+
+/**
+ * Create aggregation function
+ */
+export function createAggregator(records, func, field) {
+  const values = _.isFunction(field) ? _.map(records, field) : _.map(records, field);
+  return func(values);
+}
+
+/**
+ * Calculate percentage of parent
+ */
+export function calculatePct(records, parentRecords) {
+  return records.length / parentRecords.length;
+}
+
+/**
+ * Multi-valued groupBy - allows records to appear in multiple groups
+ */
+export function multiValuedGroupBy(recs, dimFunc) {
+  const result = {};
+  
+  recs.forEach(rec => {
+    const keys = dimFunc(rec);
+    
+    if (!Array.isArray(keys)) {
+      throw new Error("multiValuedGroupBy requires array keys");
+    }
+    
+    keys.forEach(key => {
+      if (!result[key]) {
+        result[key] = [];
+      }
+      if (!result[key].includes(rec)) {
+        result[key].push(rec);
+      }
+    });
+  });
+  
+  return result;
+}
+
+/**
+ * Find root nodes from hierarchical data (nodes that are parents but not children)
+ */
+export function findRootNodes(data, parentProp, childProp) {
+  const byParent = _.groupBy(data, parentProp);
+  const byChild = _.groupBy(data, childProp);
+  
+  // Find root nodes (appear as parent but not as child)
+  return Object.keys(byParent).filter(
+    parent => !byChild[parent]
+  );
+}
diff --git a/src/utils/groupHelpers.ts b/src/utils/groupHelpers.ts
new file mode 100644
index 0000000..070b28e
--- /dev/null
+++ b/src/utils/groupHelpers.ts
@@ -0,0 +1,125 @@
+/**
+ * Core helper utilities for grouping operations
+ * These are pure functions without Vue dependencies
+ */
+
+import _ from 'lodash';
+import type { GroupValue, PathOptions } from '../types';
+
+/**
+ * Check if entire group list is numeric
+ */
+export function isNumericGroup(groups: Record<string, any[]>): boolean {
+  return _.every(_.keys(groups), (k) => {
+    return k === null ||
+           k === undefined ||
+           (!isNaN(Number(k))) ||
+           ["null", ".", "undefined"].indexOf(k.toLowerCase()) > -1;
+  });
+}
+
+/**
+ * Filter out empty values from records
+ */
+export function filterOutEmpty<T>(
+  recs: T[],
+  dim: keyof T | ((record: T) => any)
+): T[] {
+  const func = _.isFunction(dim) ? dim : (d: T) => d[dim];
+  return recs.filter(r => 
+    !_.isEmpty(func(r)) || 
+    (_.isNumber(func(r)) && isFinite(func(r)))
+  );
+}
+
+/**
+ * Create dimension path string
+ */
+export function createDimPath<T>(
+  val: GroupValue<T>,
+  opts: PathOptions = {}
+): string {
+  const delim = opts.delim || '/';
+  const path: GroupValue<T>[] = [];
+  let ptr: GroupValue<T> | null = val;
+  
+  path.push(val);
+  while ((ptr = ptr.parent)) {
+    path.unshift(ptr);
+  }
+  
+  if (opts.noRoot) path.shift();
+  if (opts.backwards) path.reverse();
+  
+  return opts.dimName ? 
+    path.map(v => String(v.dim)).join(delim) :
+    path.map(v => String(v.value || v)).join(delim);
+}
+
+/**
+ * Create aggregation function
+ */
+export function createAggregator<T, R>(
+  records: T[],
+  func: (values: any[]) => R,
+  field?: keyof T | ((record: T) => any)
+): R {
+  const values = field
+    ? (_.isFunction(field) ? _.map(records, field) : _.map(records, field))
+    : records;
+  return func(values);
+}
+
+/**
+ * Calculate percentage of parent
+ */
+export function calculatePct<T>(records: T[], parentRecords: T[]): number {
+  return records.length / parentRecords.length;
+}
+
+/**
+ * Multi-valued groupBy - allows records to appear in multiple groups
+ */
+export function multiValuedGroupBy<T>(
+  recs: T[],
+  dimFunc: (record: T) => (string | number)[]
+): Record<string, T[]> {
+  const result: Record<string, T[]> = {};
+  
+  recs.forEach(rec => {
+    const keys = dimFunc(rec);
+    
+    if (!Array.isArray(keys)) {
+      throw new Error("multiValuedGroupBy requires array keys");
+    }
+    
+    keys.forEach(key => {
+      const keyStr = String(key);
+      if (!result[keyStr]) {
+        result[keyStr] = [];
+      }
+      if (!result[keyStr].includes(rec)) {
+        result[keyStr].push(rec);
+      }
+    });
+  });
+  
+  return result;
+}
+
+/**
+ * Find root nodes from hierarchical data (nodes that are parents but not children)
+ */
+export function findRootNodes<T>(
+  data: T[],
+  parentProp: keyof T,
+  childProp: keyof T
+): string[] {
+  const byParent = _.groupBy(data, parentProp as string);
+  const byChild = _.groupBy(data, childProp as string);
+  
+  // Find root nodes (appear as parent but not as child)
+  return Object.keys(byParent).filter(
+    parent => !byChild[parent]
+  );
+}
diff --git a/supergroup.js b/supergroup.cjs
similarity index 99%
rename from supergroup.js
rename to supergroup.cjs
index 799731e..430aad0 100644
--- a/supergroup.js
+++ b/supergroup.cjs
@@ -1095,6 +1095,6 @@ _.mixin({
     },
 });
 
-// if (typeof module !== "undefined")
-//   module.exports = _;
-export default _;
+if (typeof module !== "undefined") {
+  module.exports = _;
+}
diff --git a/test/composables.test.js b/test/composables.test.js
new file mode 100644
index 0000000..111144f
--- /dev/null
+++ b/test/composables.test.js
@@ -0,0 +1,151 @@
+/**
+ * Basic tests for Vue composables
+ * Run with: node --experimental-vm-modules test/composables.test.js
+ */
+
+import { ref, computed, nextTick, effectScope } from 'vue';
+import { useGrouping, useGroupList, useGroupValue, useGroupSelection } from '../src/index.js';
+
+// Test data
+const gradeBook = [
+    {lastName: "Gold",    firstName: "Sigfried", class: "Remedial Programming",           grade: "C", num: 2},
+    {lastName: "Gold",    firstName: "Sigfried", class: "Literary Posturing",             grade: "B", num: 3},
+    {lastName: "Gold",    firstName: "Sigfried", class: "Documenting with Pretty Colors", grade: "B", num: 3},
+    {lastName: "Sassoon", firstName: "Sigfried", class: "Remedial Programming",           grade: "A", num: 4},
+    {lastName: "Androy",  firstName: "Sigfried", class: "Remedial Programming",           grade: "B", num: 3}
+];
+
+// Helper to run tests
+function assert(condition, message) {
+  if (!condition) {
+    console.error('❌ FAIL:', message);
+    process.exit(1);
+  } else {
+    console.log('✓ PASS:', message);
+  }
+}
+
+function deepEqual(a, b, message) {
+  const aStr = JSON.stringify(a);
+  const bStr = JSON.stringify(b);
+  if (aStr !== bStr) {
+    console.error('❌ FAIL:', message);
+    console.error('  Expected:', bStr);
+    console.error('  Got:     ', aStr);
+    process.exit(1);
+  } else {
+    console.log('✓ PASS:', message);
+  }
+}
+
+// Run tests in an effect scope (simulates Vue component context)
+async function runTests() {
+  const scope = effectScope();
+  
+  await scope.run(async () => {
+    console.log('\n🧪 Testing Vue Composables\n');
+
+    // Test 1: Basic grouping
+    console.log('Test Suite: Basic Grouping');
+    const records = ref(gradeBook);
+    const grouping = useGrouping(records, 'lastName');
+    
+    assert(grouping.grouped.value.values.length === 3, 
+      'Should create 3 groups by lastName');
+    
+    deepEqual(
+      grouping.rawValues.value.sort(),
+      ["Gold", "Sassoon", "Androy"].sort(),
+      'Raw values should match expected last names'
+    );
+
+    // Test 2: Multi-level grouping
+    console.log('\nTest Suite: Multi-level Grouping');
+    const multiGroup = useGrouping(records, ['grade', 'lastName']);
+    
+    assert(multiGroup.grouped.value.values.length === 3,
+      'Should create 3 top-level groups by grade');
+    
+    deepEqual(
+      multiGroup.rawValues.value.sort(),
+      ["A", "B", "C"].sort(),
+      'Top-level values should be grades'
+    );
+
+    // Test 3: Lookup
+    console.log('\nTest Suite: Lookup Operations');
+    const gradeB = multiGroup.lookup('B');
+    assert(gradeB !== undefined, 'Should find grade B');
+    assert(gradeB.value === 'B', 'Found value should be B');
+
+    // Test 4: List operations
+    console.log('\nTest Suite: List Operations');
+    const list = useGroupList(grouping.grouped);
+    
+    assert(list.values.value.length === 3, 
+      'List should have 3 values');
+    
+    deepEqual(
+      list.rawValues.value.sort(),
+      ["Gold", "Sassoon", "Androy"].sort(),
+      'List rawValues should match'
+    );
+
+    // Test 5: Leaf nodes
+    console.log('\nTest Suite: Tree Navigation');
+    const multiList = useGroupList(multiGroup.grouped);
+    const leaves = multiList.leafNodes.value;
+    
+    assert(leaves.length === 4,
+      'Should have 4 leaf nodes in multi-level group');
+
+    // Test 6: Selection
+    console.log('\nTest Suite: Selection Management');
+    const selection = useGroupSelection(grouping.grouped);
+    
+    const firstValue = grouping.grouped.value.values[0];
+    selection.selectValue(firstValue);
+    
+    assert(selection.selectedCount.value === 1,
+      'Should have 1 selected value');
+    
+    assert(selection.isSelected(firstValue),
+      'First value should be selected');
+    
+    selection.clearSelection();
+    assert(selection.selectedCount.value === 0,
+      'Selection should be cleared');
+
+    // Test 7: Reactivity
+    console.log('\nTest Suite: Reactivity');
+    const reactiveRecords = ref([...gradeBook]);
+    const reactiveGroup = useGrouping(reactiveRecords, 'lastName');
+    
+    const initialCount = reactiveGroup.grouped.value.values.length;
+    
+    // Add a new record
+    reactiveRecords.value.push({
+      lastName: "NewPerson",
+      firstName: "Test",
+      class: "Test Class",
+      grade: "A",
+      num: 4
+    });
+    
+    // Wait for reactivity
+    await nextTick();
+    
+    assert(reactiveGroup.grouped.value.values.length === initialCount + 1,
+      'Should reactively update when records change');
+    
+    console.log('\n✅ All tests passed!\n');
+  });
+  
+  scope.stop();
+}
+
+// Run tests
+runTests().catch(err => {
+  console.error('Test error:', err);
+  process.exit(1);
+});
diff --git a/test/supergroup_vows.js b/test/supergroup_vows.cjs
similarity index 99%
rename from test/supergroup_vows.js
rename to test/supergroup_vows.cjs
index c16f541..998e082 100644
--- a/test/supergroup_vows.js
+++ b/test/supergroup_vows.cjs
@@ -4,7 +4,7 @@ var assert = require("assert");
 //XMLHttpRequest = require('xhr2');
 //var d3 = require("d3");
 var _ = require("lodash");
-require("../supergroup.js");
+require("../supergroup.cjs");
 var fs = require('fs');
 
 var suite = vows.describe("supergroup");
diff --git a/tsconfig.json b/tsconfig.json
new file mode 100644
index 0000000..13fae83
--- /dev/null
+++ b/tsconfig.json
@@ -0,0 +1,30 @@
+{
+  "compilerOptions": {
+    "target": "ES2020",
+    "module": "ESNext",
+    "lib": ["ES2020"],
+    "declaration": true,
+    "declarationMap": true,
+    "outDir": "./dist",
+    "rootDir": "./src",
+    "strict": true,
+    "esModuleInterop": true,
+    "skipLibCheck": true,
+    "forceConsistentCasingInFileNames": true,
+    "moduleResolution": "node",
+    "resolveJsonModule": true,
+    "allowSyntheticDefaultImports": true,
+    "noUnusedLocals": true,
+    "noUnusedParameters": true,
+    "noImplicitReturns": true,
+    "noFallthroughCasesInSwitch": true
+  },
+  "include": [
+    "src/**/*"
+  ],
+  "exclude": [
+    "node_modules",
+    "dist",
+    "test"
+  ]
+}