README.md

simple-undo

simple-undo is a very basic javascript undo/redo stack for managing histories of basically anything.

Initially created to help fixing an issue in drawingboard.js.

Installation

Bower

bower install simple-undo.

NPM

npm install simple-undo

Usage

If you are using simple-undo in the browser, a SimpleUndo object is exported in window after including simple-undo in your page, so it is very easy to use.

If you are using simple-undo as a nodejs module, just do var SimpleUndo = require('simple-undo');

var myObject = {};

function myObjectSerializer(done) {
    done(JSON.stringify(myObject));
}

function myObjectUnserializer(serialized) {
    myObject = JSON.parse(serialized);
}

var history = new SimpleUndo({
    maxLength: 10,
    provider: myObjectSerializer
});

myObject.foo = 'bar';
history.save();
myObject.foo = 'baz';
history.save();

history.undo(myObjectUnserializer);
// myObject.foo == 'bar'
history.redo(myObjectUnserializer);
// myObject.foo == 'baz'

Another example is available on the GitHub page of the project

Options and API

Accepted options are

• provider : required. a function to call on save, which should provide the current state of the historized object through the given done callback
• maxLength : the maximum number of items in history
• onUpdate : a function to call to notify of changes in history. Will be called on save, undo, redo and clear

SimpleUndo

• initialize (initialState) : registers the initial state of the managed object. If not call the default initial state is NULL
• save () : calls the provider and registers whatever it gives
• undo (callback) : calls the callback with the previous state of the managed object in history
• redo (callback) : calls the callback with the next state of the managed object in history
• clear () : clears the whole history, except the inital state if any
• count () : returns the count of elements in history, apart from the inital state

License

simple-undo is licensed under the terms of the Beerware license.

2014 - Matthias Jouan