Undo redo in EJ2 JavaScript Diagram control
30 Jun 202418 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
var diagram = new ej.diagrams.Diagram({
width: '100%',
height: '600px',
// Add node
nodes: [];
},'#element');
// Reverts the last action performed
diagram.undo();
// Restores the last undone action
diagram.redo();Undo/Redo for diagram can be enabled/disabled with the constraints property of diagram.
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 diagram method startGroupAction allows you to log multiple actions at a time in the history manager stack. It is easier to undo or revert the changes made in the diagram in a single undo/redo process instead of reverting every actions one by one.The diagram method endGroupAction allows you to end the group actions that are stored in the stack history. The following code illustrates how to undo/redo multiple fillColor change of a node at a time.
ej.diagrams.Diagram.Inject(ej.diagrams.UndoRedo);
var nodes = [
{
id: 'Start', width: 140, height: 50, offsetX: 300, offsetY: 50,
annotations: [{
id: 'label1',
content: 'Start'
}],
shape: { type: 'Flow', shape: 'Terminator'}
}
];
var diagram = new ej.diagrams.Diagram({
width: '100%', height: '600px', nodes: nodes
});
diagram.appendTo('#element');
//Start to group the changes
diagram.startGroupAction();
//Makes the changes
var color = ['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">
<link href="https://cdn.syncfusion.com/ej2/26.2.4/ej2-base/styles/material.css" rel="stylesheet">
<link href="https://cdn.syncfusion.com/ej2/26.2.4/ej2-buttons/styles/material.css" rel="stylesheet">
<link href="https://cdn.syncfusion.com/ej2/26.2.4/ej2-popups/styles/material.css" rel="stylesheet">
<link href="https://cdn.syncfusion.com/ej2/26.2.4/ej2-splitbuttons/styles/material.css" rel="stylesheet">
<link href="https://cdn.syncfusion.com/ej2/26.2.4/ej2-diagrams/styles/material.css" rel="stylesheet">
<link href="https://cdn.syncfusion.com/ej2/26.2.4/ej2-navigations/styles/fabric.css" rel="stylesheet">
<script src="https://cdn.syncfusion.com/ej2/26.2.4/dist/ej2.min.js" type="text/javascript"></script>
<script src="https://cdn.syncfusion.com/ej2/syncfusion-helper.js" type ="text/javascript"></script>
</head>
<body>
<div id="container">
<div id="element"></div>
</div>
<script>
var ele = document.getElementById('container');
if(ele) {
ele.style.visibility = "visible";
}
</script>
<script src="index.js" type="text/javascript"></script>
</body></html>Stack Limit
The stackLimit property of history manager is used to limits the number of actions to be stored on the history manager.
ej.diagrams.Diagram.Inject(ej.diagrams.UndoRedo);
var nodes = [{
id: 'Start',
width: 140,
height: 50,
offsetX: 300,
offsetY: 50,
annotations: [{
id: 'label1',
content: 'Start'
}],
shape: {
type: 'Flow',
shape: 'Terminator'
}
}];
var diagram= new ej.diagrams.Diagram({
width: '100%',
height: '600px',
nodes: nodes,
//Sets the stackLimit as 3
historyManager: { stackLimit: 3 },
getNodeDefaults: (node) => {
node.height = 100;
node.width = 100;
node.style.fill = '#6BA5D7';
node.style.strokeColor = 'white';
return node;
}
},'#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">
<link href="https://cdn.syncfusion.com/ej2/26.2.4/ej2-base/styles/material.css" rel="stylesheet">
<link href="https://cdn.syncfusion.com/ej2/26.2.4/ej2-buttons/styles/material.css" rel="stylesheet">
<link href="https://cdn.syncfusion.com/ej2/26.2.4/ej2-popups/styles/material.css" rel="stylesheet">
<link href="https://cdn.syncfusion.com/ej2/26.2.4/ej2-splitbuttons/styles/material.css" rel="stylesheet">
<link href="https://cdn.syncfusion.com/ej2/26.2.4/ej2-diagrams/styles/material.css" rel="stylesheet">
<link href="https://cdn.syncfusion.com/ej2/26.2.4/ej2-navigations/styles/fabric.css" rel="stylesheet">
<script src="https://cdn.syncfusion.com/ej2/26.2.4/dist/ej2.min.js" type="text/javascript"></script>
<script src="https://cdn.syncfusion.com/ej2/syncfusion-helper.js" type ="text/javascript"></script>
</head>
<body>
<div id="container">
<div id="element"></div>
</div>
<script>
var ele = document.getElementById('container');
if(ele) {
ele.style.visibility = "visible";
}
</script>
<script src="index.js" type="text/javascript"></script>
</body></html>Restrict Undo/Redo
Undo, Redo process can be avoided for particular element by using canLog property in the history manager. The following example illstrates how to prevent history entry using canLog function.
ej.diagrams.Diagram.Inject(ej.diagrams.UndoRedo);
var nodes = [
{
id: 'Start',
width: 140,
height: 50,
offsetX: 300,
offsetY: 50,
annotations: [
{
id: 'label1',
content: 'Start',
},
],
shape: {
type: 'Flow',
shape: 'Terminator',
},
},
];
var diagram = new ej.diagrams.Diagram(
{
width: '100%',
height: '600px',
nodes: nodes,
getNodeDefaults: (node) => {
node.height = 100;
node.width = 100;
node.style.fill = '#6BA5D7';
node.style.strokeColor = 'white';
return node;
},
},
'#element'
);
// canLog decide whether to add entry or not in history manager
diagram.historyManager.canLog = function (entry) {
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">
<link href="https://cdn.syncfusion.com/ej2/26.2.4/ej2-base/styles/material.css" rel="stylesheet">
<link href="https://cdn.syncfusion.com/ej2/26.2.4/ej2-buttons/styles/material.css" rel="stylesheet">
<link href="https://cdn.syncfusion.com/ej2/26.2.4/ej2-popups/styles/material.css" rel="stylesheet">
<link href="https://cdn.syncfusion.com/ej2/26.2.4/ej2-splitbuttons/styles/material.css" rel="stylesheet">
<link href="https://cdn.syncfusion.com/ej2/26.2.4/ej2-diagrams/styles/material.css" rel="stylesheet">
<link href="https://cdn.syncfusion.com/ej2/26.2.4/ej2-navigations/styles/fabric.css" rel="stylesheet">
<script src="https://cdn.syncfusion.com/ej2/26.2.4/dist/ej2.min.js" type="text/javascript"></script>
<script src="https://cdn.syncfusion.com/ej2/syncfusion-helper.js" type ="text/javascript"></script>
</head>
<body>
<div id="container">
<div id="element"></div>
</div>
<script>
var ele = document.getElementById('container');
if(ele) {
ele.style.visibility = "visible";
}
</script>
<script src="index.js" type="text/javascript"></script>
</body></html>undo/redo stack
The undoStack property is used to get the collection of undo actions which should be performed in the diagram. The redoStack property is used to get the collection of redo actions which should be performed in the diagram. The undoStack/redoStack is the read-only property.
var diagram = new ej.diagrams.Diagram({
width: '100%',
height: '600px',
nodes: nodes,
},'#element');
//get the collection of undoStack objects
let undoStack = diagram.historyManager.undoStack;
//get the collection of redoStack objects
let redoStack = diagram.historyManager.redoStack;Current entry
While performing interactions with a node or connector, the current history entry is added to the currentEntry property of the historyManager..
The following code shows how to get the current entry from the diagram history:
ej.diagrams.Diagram.Inject(ej.diagrams.UndoRedo);
var nodes = [
{
id: 'Start',
width: 140,
height: 50,
offsetX: 300,
offsetY: 50,
annotations: [
{
id: 'label1',
content: 'Perform interaction with node to get current entry',
},
],
shape: {
type: 'Flow',
shape: 'Terminator',
},
},
];
var diagram = new ej.diagrams.Diagram(
{
width: '100%',
height: '600px',
nodes: nodes,
getNodeDefaults: (node) => {
node.height = 100;
node.width = 100;
node.style.fill = '#6BA5D7';
node.style.strokeColor = 'white';
return node;
},
historyChange: function (args) {
//To get current entry
console.log(diagram.historyManager.currentEntry);
},
},
'#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">
<link href="https://cdn.syncfusion.com/ej2/26.2.4/ej2-base/styles/material.css" rel="stylesheet">
<link href="https://cdn.syncfusion.com/ej2/26.2.4/ej2-buttons/styles/material.css" rel="stylesheet">
<link href="https://cdn.syncfusion.com/ej2/26.2.4/ej2-popups/styles/material.css" rel="stylesheet">
<link href="https://cdn.syncfusion.com/ej2/26.2.4/ej2-splitbuttons/styles/material.css" rel="stylesheet">
<link href="https://cdn.syncfusion.com/ej2/26.2.4/ej2-diagrams/styles/material.css" rel="stylesheet">
<link href="https://cdn.syncfusion.com/ej2/26.2.4/ej2-navigations/styles/fabric.css" rel="stylesheet">
<script src="https://cdn.syncfusion.com/ej2/26.2.4/dist/ej2.min.js" type="text/javascript"></script>
<script src="https://cdn.syncfusion.com/ej2/syncfusion-helper.js" type ="text/javascript"></script>
</head>
<body>
<div id="container">
<div id="element"></div>
</div>
<script>
var ele = document.getElementById('container');
if(ele) {
ele.style.visibility = "visible";
}
</script>
<script src="index.js" type="text/javascript"></script>
</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 historyManager 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 historyManager by using the client-side method push of historyManager.
The following code example illustrates how to save the existing property values.
var diagram = new ej.diagrams.Diagram({
width: '100%',
height: '600px',
},'#element');
//Creates a custom entry
var entry = {
undoObject: diagram.nodes[0];
};
// adds that to history list
diagram.historyManager.push(entry);History change event
The historyChange event triggers, whenever the interaction of the node and connector is take place. When interacting, the entries get added to the history manager to trigger this event.
let diagram = new ej.diagrams.Diagram({
width: '100%',
height: '600px',
nodes: nodes,
},'#element');
// history change event
diagram.historyChange = (arg) => {
//causes of history change
let cause: string = arg.cause;
}While interacting with diagram, this event can be used to do the customization.