table-modifiable Web Component

A web component that enables users to hide & show columns on an HTML table.

Demo

Live Demo (Source)

Additional demos:

• ESM CDN Demo (Source)
• Unpkg CDN Demo (Source)

Installation

npm install @aarongustafson/table-modifiable

Usage

Option 1: Auto-define the custom element (easiest)

Import the package to automatically define the <table-modifiable> custom element:

import '@aarongustafson/table-modifiable';

Or use the define-only script in HTML:

<script src="./node_modules/@aarongustafson/table-modifiable/define.js" type="module"></script>

Option 2: Import the class and define manually

Import the class and define the custom element with your preferred tag name:

import { TableModifiableElement } from '@aarongustafson/table-modifiable/table-modifiable.js';

customElements.define('my-custom-name', TableModifiableElement);

You can also call the provided helper to register the element without importing the class:

import { defineTableModifiable } from '@aarongustafson/table-modifiable/define.js';

defineTableModifiable('my-custom-name');

Basic Example

<table-modifiable removable="Name,Email,Phone" start-with="Name,Email">
  <table>
    <thead>
      <tr>
        <th>Name</th>
        <th>Email</th>
        <th>Phone</th>
      </tr>
    </thead>
    <tbody>
      <tr>
        <td>John Doe</td>
        <td>john@example.com</td>
        <td>555-1234</td>
      </tr>
    </tbody>
  </table>
</table-modifiable>

Attributes

Attribute	Type	Default	Description
removable	string	""	Comma-separated list of all column names that can be shown/hidden
start-with	string	(all removable)	Comma-separated list of which columns should be visible by default. If not specified, all removable columns will be shown initially
button-label	string	"Modify Table"	Text label for the toggle button
button-aria-label	string	(same as button-label)	Accessible label for the toggle button. Use this to provide a more descriptive label for screen readers if needed
tools-label	string	"Show/Hide Columns"	Heading text for the popover panel

Properties

All of the attributes above have matching camelCase properties (removable, startWith, buttonLabel, buttonAriaLabel, toolsLabel). Setting a property updates the corresponding attribute and schedules the component to re-render.

const modifiable = document.querySelector('table-modifiable');
modifiable.removable = 'Name,Email';
modifiable.startWith = 'Name';

Events

The component fires custom events that you can listen to:

Event	Description	Detail
table-modifiable:change	Fired when a column's visibility is toggled	{ column: string, visible: boolean }

Example Event Handling

const element = document.querySelector('table-modifiable');

element.addEventListener('table-modifiable:change', (event) => {
  console.log(`Column "${event.detail.column}" is now ${event.detail.visible ? 'visible' : 'hidden'}`);
});

CSS Custom Properties

Property	Default	Description
--table-modifiable-tool-bg	(none)	Background color for the modification tools popover
--table-modifiable-tool-color	(none)	Text color for the modification tools popover

Example Styling

You can style the generated elements directly to customize the appearance:

/* Style the toggle button */
.modification-tools-toggle {
  background: #0969da;
  color: white;
  border: none;
  padding: 0.5rem 1rem;
  border-radius: 4px;
  font-size: 1rem;
  cursor: pointer;
}

.modification-tools-toggle:hover {
  background: #0860ca;
}

/* Style the popover */
.modification-tools {
  background: var(--table-modifiable-tool-bg, white);
  color: var(--table-modifiable-tool-color, #333);
  padding: 1rem;
  border-radius: 6px;
  border: 1px solid #d0d7de;
  box-shadow: 0 8px 24px rgba(140, 149, 159, 0.2);
  min-width: 250px;
}

.modification-tools-heading {
  font-weight: bold;
  display: block;
  margin-bottom: 0.75rem;
  font-size: 1.1rem;
}

.modification-tools ul {
  list-style: none;
  padding: 0;
  margin: 0;
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.modification-tools li {
  margin: 0;
}

.modification-tools label {
  cursor: pointer;
  user-select: none;
}

How It Works

This component wraps an HTML table and adds interactive controls to show/hide columns:

1. Place your table inside the component: The component uses Light DOM, so your table remains in the regular DOM and is fully accessible.

2. Specify removable columns: Use the removable attribute to list which columns can be toggled. The column names must match the text content of the <th> elements in the first header row exactly.

3. Set initial visibility: Optionally use start-with to specify which columns should be visible when the page loads. Any columns in removable but not in start-with will be hidden initially.

4. Toggle via popover: The component creates a button that opens a popover with checkboxes. Users can check/uncheck these to show/hide the corresponding columns. The popover uses the native Popover API.

5. Customize labels: Use the button-label, button-aria-label, and tools-label attributes to customize the text shown to users.

Note: This component works with simple tables (one header row, matching body cells). It does not support colspan or rowspan attributes.

Advanced Examples

Table with Multiple Columns

<table-modifiable removable="Product,Price,Stock,Category" start-with="Product,Price">
  <table>
    <thead>
      <tr>
        <th>Product</th>
        <th>Price</th>
        <th>Stock</th>
        <th>Category</th>
      </tr>
    </thead>
    <tbody>
      <tr>
        <td>Widget</td>
        <td>$9.99</td>
        <td>42</td>
        <td>Tools</td>
      </tr>
    </tbody>
  </table>
</table-modifiable>

Customizing Labels

<table-modifiable
  removable="Name,Email,Phone,Address"
  start-with="Name,Email"
  button-label="Customize Columns"
  button-aria-label="Customize which columns are visible in the table"
  tools-label="Select Visible Columns">
  <table>
    <thead>
      <tr>
        <th>Name</th>
        <th>Email</th>
        <th>Phone</th>
        <th>Address</th>
      </tr>
    </thead>
    <tbody>
      <tr>
        <td>Jane Doe</td>
        <td>jane@example.com</td>
        <td>555-5678</td>
        <td>123 Main St</td>
      </tr>
    </tbody>
  </table>
</table-modifiable>

TypeScript

This package ships bundled type definitions (table-modifiable.d.ts). You can import the element type, the change event payload, and the registration helper:

import type {
  TableModifiableElement,
  TableModifiableChangeEvent,
} from '@aarongustafson/table-modifiable/table-modifiable.js';
import { defineTableModifiable } from '@aarongustafson/table-modifiable/define.js';

defineTableModifiable();

const element = document.querySelector('table-modifiable') as TableModifiableElement;

element.addEventListener(
  'table-modifiable:change',
  (event: TableModifiableChangeEvent) => {
    console.log(event.detail.column, event.detail.visible);
  },
);

Browser Support

This component uses modern web standards:

• Custom Elements v1
• ES Modules
• Popover API

For older browsers, you may need polyfills.

Development

# Install dependencies
npm install

# Run tests
npm test

# Run tests with coverage
npm run test:coverage

# Lint code
npm run lint

# Format code
npm run format

# View demo
open demo/index.html

License

MIT © Aaron Gustafson