undo-redo

A simple to use, powerful all-purpose undo-redo stack for JavaScript (browser and Node).

Features

• Lightweight, efficient and easy to use
• Browser + Nodejs support
• Add any kind of data to the stack (text, images, canvas data, objects, arrays etc.).
• Data is stored AS-IS for flexibility (simply deep-clone objects beforehand if needed)
• Single undo() call, returns object for new state
• Single redo() call, returns object for new state (if possible)
• Can use callback functions on undo/redo
• Set optional limit (with FIFO)
• Get undo/redo status, count and pointer
• Get or set stack content for storage.
• HTML documentation included in addition to source documentation

See the demos directory for example usage.

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Install

undo-redo can be installed in various ways:

• Git using HTTPS: git clone https://github.com/epistemex/undo-redo.git
• Git using SSH: git clone git@github.com:epistemex/undo-redo.git
• For Node.js - NPM: npm i undo-redo-js

Usage

Include script, create an instance:

const stack = new UndoRedo();

Add some states to the stack:

stack.add(myCurrentData);   // push data to stack, each add is one undo state

To undo call the undo() method. Data from the previous state is returned. If at beginning of stack null will be returned:

let data = stack.undo();    // return previous state data
if ( data ) { /* set data */ }

If no add() was called since last undo, redo() can be called. The data for new current state is returned, or null if a redo wasn't possible:

let data = stack.redo();    // redo and return data for next state if any
if ( data ) { /* set data */ }

For more advanced usage callbacks can be used:

const stack = new UndoRedo();
stack.onundo = function(data) { /* data or null */ }
stack.onredo = function(data) { /* data or null */ }
//...
stack.undo();               // invokes callback

Callbacks can be set via options:

const stack = new UndoRedo({
  limit : 100,       // defaults to -1 = unlimited
  onUndo: undoCallback,
  onRedo: redoCallback
});

From Node

Require the package:

const UndoRedo = require("undo-redo-js").UndoRedo;

Create a stack:

const stack = new UndoRedo();

License

Released under MIT license.

© 2015-2018, 2024 Epistemex