Update README.md

Author: ArthurClemens

README.md

@@ -1,343 +1,3 @@
 # Undo Manager
 
-Simple undo manager to provide undo and redo actions in JavaScript applications.
-
-
-- [Demos](#demos)
-- [Installation](#installation)
-- [Example](#example)
-- [Updating the UI](#updating-the-ui)
-- [Methods](#methods)
-  - [add](#add)
-  - [undo](#undo)
-  - [redo](#redo)
-  - [clear](#clear)
-  - [setLimit](#setlimit)
-  - [hasUndo](#hasundo)
-  - [hasRedo](#hasredo)
-  - [setCallback](#setcallback)
-  - [getIndex](#getindex)
-  - [getCommands](#getcommands)
-- [Use with CommonJS](#use-with-commonjs)
-- [Use with RequireJS](#use-with-requirejs)
-
-
-## Demos
-
-* [CodeSandbox with RGB color slider](https://codesandbox.io/s/undo-manager-color-sliders-z4myoj)
-* [Undo Manager with canvas drawing](https://arthurclemens.github.io/JavaScript-Undo-Manager/)
-* [JSBin demo, also with canvas](http://jsbin.com/tidibi/edit?js,output)
-
-
-## Installation
-
-```
-npm install undo-manager
-```
-
-
-## Example
-
-Actions (typing a character, moving an object) are structured as command pairs: one command for destruction (undo) and one for creation (redo). Each pair is added to the undo stack:
-
-```js
-const undoManager = new UndoManager();
-undoManager.add({
-  undo: function() {
-    // ...
-  },
-  redo: function() {
-    // ...
-  }
-});
-```
-
-To make an action undoable, you'd add an undo/redo command pair to the undo manager:
-
-```js
-const undoManager = new UndoManager();
-const people = {}; 
-
-function addPerson(id, name) {
-  people[id] = name;
-};
-
-function removePerson(id) {
-  delete people[id];
-};
-
-function createPerson(id, name) {
-  // first creation
-  addPerson(id, name);
-
-  // make undoable
-  undoManager.add({
-    undo: () => removePerson(id),
-    redo: () => addPerson(id, name)
-  });
-}
-
-createPerson(101, "John");
-createPerson(102, "Mary");
-
-console.log(people); // logs: {101: "John", 102: "Mary"}
-
-undoManager.undo();
-console.log(people); // logs: {101: "John"}
-
-undoManager.undo();
-console.log(people); // logs: {}
-
-undoManager.redo();
-console.log(people); // logs: {101: "John"}
-```
-
-## Updating the UI
-
-TL;DR UI that relies on undo manager state - for example `hasUndo` and `hasRedo` - needs to be updated using the callback function provided with `setCallback`. This ensures that all internal state has been resolved before the UI is repainted.
-
-Let's say we have an update function that conditionally disables the undo and redo buttons:
-
-```js
-function updateUI() {
-  btn_undo.disabled = !undoManager.hasUndo();
-  btn_redo.disabled = !undoManager.hasRedo();
-}
-```
-
-You might be inclined to call the update in the undo/redo command pair:
-
-```js
-// wrong approach, don't copy
-const undoManager = new UndoManager();
-const states = [];
-
-function updateState(newState) {
-  states.push(newState);
-  updateUI();
-
-  undoManager.add({
-    undo: function () {
-      states.pop();
-      updateUI(); // <= this will lead to inconsistent UI state
-    },
-    redo: function () {
-      states.push(newState);
-      updateUI(); // <= this will lead to inconsistent UI state
-    }
-  });
-}
-```
-
-Instead, pass the update function to `setCallback`:
-
-```js
-// recommended approach
-const undoManager = new UndoManager();
-undoManager.setCallback(updateUI);
-
-const states = [];
-
-function updateState(newState) {
-  states.push(newState);
-  updateUI();
-
-  undoManager.add({
-    undo: function () {
-      states.pop();
-    },
-    redo: function () {
-      states.push(newState);
-    }
-  });
-}
-```
-
-## Methods
-
-### add
-
-Adds an undo/redo command pair to the stack.
-
-```js
-function createPerson(id, name) {
-  // first creation
-  addPerson(id, name);
-
-  // make undoable
-  undoManager.add({
-    undo: () => removePerson(id),
-    redo: () => addPerson(id, name)
-  });
-}
-```
-
-Optionally add a `groupId` to identify related command pairs. Undo and redo actions will then be performed on all adjacent command pairs with that group id.
-
-```js
-undoManager.add({
-  groupId: 'auth',
-  undo: () => removePerson(id),
-  redo: () => addPerson(id, name)
-});
-```
-
-
-### undo
-
-Performs the undo action.
-
-```js
-undoManager.undo();
-```
-
-If a `groupId` was set, the undo action will be performed on all adjacent command pairs with that group id.
-
-### redo
-
-Performs the redo action.
-
-```js
-undoManager.redo();
-```
-
-If a `groupId` was set, the redo action will be performed on all adjacent command pairs with that group id.
-
-### clear
-
-Clears all stored states.
-
-```js
-undoManager.clear();
-```
-
-### setLimit
-
-Set the maximum number of undo steps. Default: 0 (unlimited).
-
-```js
-undoManager.setLimit(limit);
-```
-
-### hasUndo
-
-Tests if any undo actions exist.
-
-```js
-const hasUndo = undoManager.hasUndo();
-```
-
-### hasRedo
-
-Tests if any redo actions exist.
-
-```js
-const hasRedo = undoManager.hasRedo();
-```
-
-### setCallback
-
-Get notified on changes. Pass a function to be called on undo and redo actions.
-
-```js
-undoManager.setCallback(myCallback);
-```
-
-### getIndex
-
-Returns the index of the actions list.
-
-```js
-const index = undoManager.getIndex();
-```
-
-### getCommands
-
-Returns the list of queued commands, optionally filtered by group id.
-
-```js
-const commands = undoManager.getCommands();
-const commands = undoManager.getCommands(groupId);
-```
-
-## Use with CommonJS
-
-```bash
-npm install undo-manager
-```
-
-```js
-const UndoManager = require('undo-manager')
-```
-
-If you only need a single instance of UndoManager throughout your application, it may be wise to create a module that exports a singleton:
-
-```js
-// undoManager.js
-const undoManager = require('undo-manager'); // require the lib from node_modules
-let singleton = undefined;
-
-if (!singleton) {
-  singleton = new undoManager();
-}
-
-module.exports = singleton;
-```
-
-Then in your app:
-
-```js
-// app.js
-const undoManager = require('undoManager');
-
-undoManager.add(...);
-undoManager.undo();
-```
-
-
-## Use with RequireJS
-
-If you are using RequireJS, you need to use the `shim` config parameter.
-
-Assuming `require.js` and `domReady.js` are located in `js/extern`, the `index.html` load call would be:
-
-```html
-<script src="js/extern/require.js" data-main="js/demo"></script>
-```
-
-And `demo.js` would look like this:
-
-```js
-requirejs.config({
-  baseUrl: "js",
-  paths: {
-    domReady: "extern/domReady",
-    app: "../demo",
-    undomanager: "../../js/undomanager",
-    circledrawer: "circledrawer"
-  },
-  shim: {
-    "undomanager": {
-      exports: "UndoManager"
-    },
-    "circledrawer": {
-      exports: "CircleDrawer"
-    }
-  }
-});
-
-require(["domReady", "undomanager", "circledrawer"], function(domReady, UndoManager, CircleDrawer) {
-  "use strict";
-
-  let undoManager,
-    circleDrawer,
-    btnUndo,
-    btnRedo,
-    btnClear;
-
-  undoManager = new UndoManager();
-  circleDrawer = new CircleDrawer("view", undoManager);
-
-  // etcetera
-});
-```
+Migrated to https://codeberg.org/ArthurClemens/JavaScript-Undo-Manager