Undo redo in EJ2 TypeScript Diagram control
25 Apr 202315 minutes to read
Diagram tracks the history of actions that are performed after initializing the diagram and provides support to reverse and restore those changes.
Undo and redo
Diagram provides built-in support to track the changes that are made through interaction and through public APIs. The changes can be reverted or restored either through shortcut keys or through commands.
Note: If you want to use Undo-Redo in diagram, you need to inject UndoRedo in the diagram.
Undo/redo through shortcut keys
Undo/redo commands can be executed through shortcut keys. Shortcut key for undo is Ctrl+z and shortcut key for redo is Ctrl+y.
Undo/redo through public APIs
The client-side methods undo and redo help you to revert/restore the changes. The following code example illustrates how to undo/redo the changes through script.
// initialize diagram component
let diagram: Diagram = new Diagram({
width: '100%',
height: '600px',
// Add node
nodes: [];
});
// render initialized diagram
diagram.appendTo('#element');
// Reverts the last action performed
diagram.undo();
// Restores the last undone action
diagram.redo();When a change in the diagram is reverted or restored (undo/redo), the historyChange event gets triggered.
Group multiple changes
History list allows to revert or restore multiple changes through a single undo/redo command. For example, revert/restore the fill color change of multiple elements at a time.
The client-side method startGroupAction is used to notify the diagram to start grouping the changes. The client-side method endGroupAction is used to notify to stop grouping the changes. The following code illustrates how to undo/redo fillColor change of multiple elements at a time.
import {
Diagram, NodeModel, ConnectorModel, UndoRedo
} from '@syncfusion/ej2-diagrams';
Diagram.Inject(UndoRedo);
let nodes: NodeModel[] = [{
id: 'Start',
width: 140,
height: 50,
offsetX: 300,
offsetY: 50,
annotations: [{
id: 'label1',
content: 'Start'
}],
shape: {
type: 'Flow',
shape: 'Terminator'
}
}];
let diagram: Diagram = new Diagram({
width: '100%',
height: '600px',
nodes: nodes,
getNodeDefaults: (node: NodeModel) => {
node.height = 100;
node.width = 100;
node.style.fill = '#6BA5D7';
node.style.strokeColor = 'white';
return node;
}
});
diagram.appendTo('#element');
//Start to group the changes
diagram.startGroupAction();
//Makes the changes
let color: string[] = ['black', 'red', 'green', 'yellow']
for (var i = 0; i < color.length; i++) {
// Updates the fillColor for all the child elements.
diagram.nodes[0].style.fill = color[i];
diagram.dataBind();
}
//Ends grouping the changes
diagram.endGroupAction();<!DOCTYPE html>
<html lang="en">
<head>
<title>EJ2 Diagram</title>
<meta charset="utf-8" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<meta name="description" content="Typescript UI Controls" />
<meta name="author" content="Syncfusion" />
<link href="index.css" rel="stylesheet" />
<script src="https://cdnjs.cloudflare.com/ajax/libs/systemjs/0.19.38/system.js"></script>
<link href="https://cdn.syncfusion.com/ej2/23.1.36/ej2-base/styles/material.css" rel="stylesheet" />
<link href="https://cdn.syncfusion.com/ej2/23.1.36/ej2-buttons/styles/material.css" rel="stylesheet" />
<link href="https://cdn.syncfusion.com/ej2/23.1.36/ej2-popups/styles/material.css" rel="stylesheet" />
<link href="https://cdn.syncfusion.com/ej2/23.1.36/ej2-splitbuttons/styles/material.css" rel="stylesheet" />
<link href="https://cdn.syncfusion.com/ej2/23.1.36/ej2-diagrams/styles/material.css" rel="stylesheet" />
<link href="https://cdn.syncfusion.com/ej2/23.1.36/ej2-navigations/styles/fabric.css" rel="stylesheet" />
<script src="systemjs.config.js"></script>
<script src="https://cdn.syncfusion.com/ej2/syncfusion-helper.js" type ="text/javascript"></script>
</head>
<body>
<div id='loader'>Loading....</div>
<div id='container'>
<div id='element'></div>
</div>
</body>
</html>Track custom changes
Diagram provides options to track the changes that are made to custom properties. For example, in case of an employee relationship diagram, track the changes in the employee information. The historyList of the diagram enables you to track such changes. The following example illustrates how to track such custom property changes.
Before changing the employee information, save the existing information to historyList by using the client-side method push of historyList.
The historyList canLog method can be used which takes a history entry as argument and returns whether the specific entry can be added or not.
The following code example illustrates how to save the existing property values.
let diagram: Diagram = new Diagram({
width: '100%',
height: '600px',
});
diagram.appendTo('#element');
//Creates a custom entry
let entry: HistoryEntry = {
undoObject: diagram.nodes[0];
};
// adds that to history list
diagram.historyList.push(entry);
diagram.dataBind();canLog
canLog in the history list, which takes a history entry as argument and returns whether the specific entry can be added or not.
import {
Diagram, NodeModel, ConnectorModel, UndoRedo
} from '@syncfusion/ej2-diagrams';
Diagram.Inject(UndoRedo);
let nodes: NodeModel[] = [{
id: 'Start',
width: 140,
height: 50,
offsetX: 300,
offsetY: 50,
annotations: [{
id: 'label1',
content: 'Start'
}],
shape: {
type: 'Flow',
shape: 'Terminator'
}
}];
let diagram: Diagram = new Diagram({
width: '100%',
height: '600px',
nodes: nodes,
getNodeDefaults: (node: NodeModel) => {
node.height = 100;
node.width = 100;
node.style.fill = '#6BA5D7';
node.style.strokeColor = 'white';
return node;
}
});
diagram.appendTo('#element');
// canLog decide whether the entry add or not in history List
diagram.historyList.canLog = function(entry: HistoryEntry) {
entry.cancel = true;
return entry;
}<!DOCTYPE html>
<html lang="en">
<head>
<title>EJ2 Diagram</title>
<meta charset="utf-8" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<meta name="description" content="Typescript UI Controls" />
<meta name="author" content="Syncfusion" />
<link href="index.css" rel="stylesheet" />
<script src="https://cdnjs.cloudflare.com/ajax/libs/systemjs/0.19.38/system.js"></script>
<link href="https://cdn.syncfusion.com/ej2/23.1.36/ej2-base/styles/material.css" rel="stylesheet" />
<link href="https://cdn.syncfusion.com/ej2/23.1.36/ej2-buttons/styles/material.css" rel="stylesheet" />
<link href="https://cdn.syncfusion.com/ej2/23.1.36/ej2-popups/styles/material.css" rel="stylesheet" />
<link href="https://cdn.syncfusion.com/ej2/23.1.36/ej2-splitbuttons/styles/material.css" rel="stylesheet" />
<link href="https://cdn.syncfusion.com/ej2/23.1.36/ej2-diagrams/styles/material.css" rel="stylesheet" />
<link href="https://cdn.syncfusion.com/ej2/23.1.36/ej2-navigations/styles/fabric.css" rel="stylesheet" />
<script src="systemjs.config.js"></script>
<script src="https://cdn.syncfusion.com/ej2/syncfusion-helper.js" type ="text/javascript"></script>
</head>
<body>
<div id='loader'>Loading....</div>
<div id='container'>
<div id='element'></div>
</div>
</body>
</html>Track undo/redo actions
The historyList undoStack property is used to get the collection of undo actions which should be performed in the diagram.
The undoStack/redoStack is the read-only property.
let diagram: Diagram = new Diagram({
width: '100%',
height: '600px',
nodes: nodes,
});
diagram.appendTo('#element');
//get the collection of undoStack objects
let undoStack = diagram.historyList.undoStack;
//get the collection of redoStack objects
let redoStack = diagram.historyList.redoStack;History change event
The historyChange event triggers, whenever the interaction of the node and connector is take place.
let diagram: Diagram = new Diagram({
width: '100%',
height: '600px',
nodes: nodes,
});
diagram.appendTo('#element');
// history change event
diagram.historyChange = (arg: IHistoryChangeArgs) => {
//causes of history change
let cause: string = arg.cause;
}Stack Limit
The stackLimit property of history manager is used to limits the number of actions to be stored on the history manager.
import {
Diagram, NodeModel, ConnectorModel, UndoRedo
} from '@syncfusion/ej2-diagrams';
Diagram.Inject(UndoRedo);
let nodes: NodeModel[] = [{
id: 'Start',
width: 140,
height: 50,
offsetX: 300,
offsetY: 50,
annotations: [{
id: 'label1',
content: 'Start'
}],
shape: {
type: 'Flow',
shape: 'Terminator'
}
}];
let diagram: Diagram = new Diagram({
width: '100%',
height: '600px',
nodes: nodes,
historyManager: { stackLimit: 3 },
getNodeDefaults: (node: NodeModel) => {
node.height = 100;
node.width = 100;
node.style.fill = '#6BA5D7';
node.style.strokeColor = 'white';
return node;
}
});
diagram.appendTo('#element');<!DOCTYPE html>
<html lang="en">
<head>
<title>EJ2 Diagram</title>
<meta charset="utf-8" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<meta name="description" content="Typescript UI Controls" />
<meta name="author" content="Syncfusion" />
<link href="index.css" rel="stylesheet" />
<script src="https://cdnjs.cloudflare.com/ajax/libs/systemjs/0.19.38/system.js"></script>
<link href="https://cdn.syncfusion.com/ej2/23.1.36/ej2-base/styles/material.css" rel="stylesheet" />
<link href="https://cdn.syncfusion.com/ej2/23.1.36/ej2-buttons/styles/material.css" rel="stylesheet" />
<link href="https://cdn.syncfusion.com/ej2/23.1.36/ej2-popups/styles/material.css" rel="stylesheet" />
<link href="https://cdn.syncfusion.com/ej2/23.1.36/ej2-splitbuttons/styles/material.css" rel="stylesheet" />
<link href="https://cdn.syncfusion.com/ej2/23.1.36/ej2-diagrams/styles/material.css" rel="stylesheet" />
<link href="https://cdn.syncfusion.com/ej2/23.1.36/ej2-navigations/styles/fabric.css" rel="stylesheet" />
<script src="systemjs.config.js"></script>
<script src="https://cdn.syncfusion.com/ej2/syncfusion-helper.js" type ="text/javascript"></script>
</head>
<body>
<div id='loader'>Loading....</div>
<div id='container'>
<div id='element'></div>
</div>
</body>
</html>Retain Selection
You can retain a selection at undo/redo operation by using the client-side API Method called updateSelection. Using this method, we can select a diagram objects.
let diagram: Diagram = new Diagram({
width: '100%',
height: '600px',
updateSelection: (object: NodeModel, diagram: Diagram) => {
let selArr = [];
selArr.push(object)
diagram.select(selArr);
},
nodes: nodes,
});
diagram.appendTo('#element');