| /bower_components/simple-undo/lib/simple-undo.js |
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| @@ -0,0 +1,113 @@ |
|---|
| (function() { |
| |
| 'use strict'; |
| |
| /** |
| * SimpleUndo is a very basic javascript undo/redo stack for managing histories of basically anything. |
| * |
| * 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 |
| * * `opUpdate` : a function to call to notify of changes in history. Will be called on `save`, `undo`, `redo` and `clear` |
| * } |
| * |
| */ |
| var SimpleUndo = function(options) { |
| |
| var settings = options ? options : {}; |
| var defaultOptions = { |
| provider: function() { |
| throw new Error("No provider!"); |
| }, |
| maxLength: 30, |
| onUpdate: function() {} |
| }; |
| |
| this.provider = (typeof settings.provider != 'undefined') ? settings.provider : defaultOptions.provider; |
| this.maxLength = (typeof settings.maxLength != 'undefined') ? settings.maxLength : defaultOptions.maxLength; |
| this.onUpdate = (typeof settings.onUpdate != 'undefined') ? settings.onUpdate : defaultOptions.onUpdate; |
| |
| this.initialItem = null; |
| this.clear(); |
| }; |
| |
| function truncate (stack, limit) { |
| while (stack.length > limit) { |
| stack.shift(); |
| } |
| } |
| |
| SimpleUndo.prototype.initialize = function(initialItem) { |
| this.stack[0] = initialItem; |
| this.initialItem = initialItem; |
| }; |
| |
| |
| SimpleUndo.prototype.clear = function() { |
| this.stack = [this.initialItem]; |
| this.position = 0; |
| this.onUpdate(); |
| }; |
| |
| SimpleUndo.prototype.save = function() { |
| this.provider(function(current) { |
| truncate(this.stack, this.maxLength); |
| this.position = Math.min(this.position,this.stack.length - 1); |
| |
| this.stack = this.stack.slice(0, this.position + 1); |
| this.stack.push(current); |
| this.position++; |
| this.onUpdate(); |
| }.bind(this)); |
| }; |
| |
| SimpleUndo.prototype.undo = function(callback) { |
| if (this.canUndo()) { |
| var item = this.stack[--this.position]; |
| this.onUpdate(); |
| |
| if (callback) { |
| callback(item); |
| } |
| } |
| }; |
| |
| SimpleUndo.prototype.redo = function(callback) { |
| if (this.canRedo()) { |
| var item = this.stack[++this.position]; |
| this.onUpdate(); |
| |
| if (callback) { |
| callback(item); |
| } |
| } |
| }; |
| |
| SimpleUndo.prototype.canUndo = function() { |
| return this.position > 0; |
| }; |
| |
| SimpleUndo.prototype.canRedo = function() { |
| return this.position < this.count(); |
| }; |
| |
| SimpleUndo.prototype.count = function() { |
| return this.stack.length - 1; // -1 because of initial item |
| }; |
| |
| |
| |
| |
| |
| //exports |
| // node module |
| if (typeof module != 'undefined') { |
| module.exports = SimpleUndo; |
| } |
| |
| // browser global |
| if (typeof window != 'undefined') { |
| window.SimpleUndo = SimpleUndo; |
| } |
| |
| })(); |
