## UndoManager This module allows to manage the stack of changes applied in canvas. Once the editor is instantiated you can use its API. Before using these methods you should get the module from the instance ```js const um = editor.UndoManager; ``` - [getConfig][1] - [add][2] - [remove][3] - [removeAll][4] - [start][5] - [stop][6] - [undo][7] - [undoAll][8] - [redo][9] - [redoAll][10] - [hasUndo][11] - [hasRedo][12] - [getStack][13] - [clear][14] ## getConfig Get module configurations ### Examples ```javascript const config = um.getConfig(); // { ... } ``` Returns **[Object][15]** Configuration object ## add Add an entity (Model/Collection) to track Note: New Components and CSSRules will be added automatically ### Parameters - `entity` **(Model | Collection)** Entity to track ### Examples ```javascript um.add(someModelOrCollection); ``` Returns **this** ## remove Remove and stop tracking the entity (Model/Collection) ### Parameters - `entity` **(Model | Collection)** Entity to remove ### Examples ```javascript um.remove(someModelOrCollection); ``` Returns **this** ## removeAll Remove all entities ### Examples ```javascript um.removeAll(); ``` Returns **this** ## start Start/resume tracking changes ### Examples ```javascript um.start(); ``` Returns **this** ## stop Stop tracking changes ### Examples ```javascript um.stop(); ``` Returns **this** ## undo Undo last change ### Examples ```javascript um.undo(); ``` Returns **this** ## undoAll Undo all changes ### Examples ```javascript um.undoAll(); ``` Returns **this** ## redo Redo last change ### Examples ```javascript um.redo(); ``` Returns **this** ## redoAll Redo all changes ### Examples ```javascript um.redoAll(); ``` Returns **this** ## hasUndo Checks if exists an available undo ### Examples ```javascript um.hasUndo(); ``` Returns **[Boolean][16]** ## hasRedo Checks if exists an available redo ### Examples ```javascript um.hasRedo(); ``` Returns **[Boolean][16]** ## getStack Get stack of changes ### Examples ```javascript const stack = um.getStack(); stack.each(item => ...); ``` Returns **Collection** ## clear Clear the stack ### Examples ```javascript um.clear(); ``` Returns **this** [1]: #getconfig [2]: #add [3]: #remove [4]: #removeall [5]: #start [6]: #stop [7]: #undo [8]: #undoall [9]: #redo [10]: #redoall [11]: #hasundo [12]: #hasredo [13]: #getstack [14]: #clear [15]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Object [16]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Boolean