Getting started in EJ2 TypeScript Check box control

3 Nov 20239 minutes to read

This section explains how to create a simple CheckBox, and configure its available functionalities in TypeScript, using Essential JS 2 quickstart seed repository.

This application is integrated with the webpack.config.js configuration and uses the latest version of the webpack-cli. It requires node v14.15.0 or higher. For more information about webpack and its features, refer to the webpack documentation.

Dependencies

The following list of dependencies are required to use the CheckBox component in your application the.

|-- @syncfusion/ej2-buttons
    |-- @syncfusion/ej2-base

Set up development environment

Open the command prompt from the required directory, and run the following command to clone the Syncfusion JavaScript (Essential JS 2) quickstart project from GitHub.

git clone https://github.com/SyncfusionExamples/ej2-quickstart-webpack- ej2-quickstart

After cloning the application in the ej2-quickstart folder, run the following command line to navigate to the ej2-quickstart folder.

cd ej2-quickstart

Add Syncfusion JavaScript packages

Syncfusion JavaScript (Essential JS 2) packages are available on the npmjs.com public registry. You can install all Syncfusion JavaScript (Essential JS 2) controls in a single @syncfusion/ej2 package or individual packages for each control.

The quickstart application is preconfigured with the dependent @syncfusion/ej2 package in the ~/package.json file. Use the following command to install the dependent npm packages from the command prompt.

npm install

Import the Syncfusion CSS styles

To render Checkbox component, need to import Button and its dependent components styles as given below in the ~/src/styles/styles.css file, as shown below:

style.css
@import "../../node_modules/@syncfusion/ej2-base/styles/material.css";
@import "../../node_modules/@syncfusion/ej2-buttons/styles/material.css";

Add CheckBox to the project

Add the HTML input tag with id attribute as the element to your index.html file.

[src/index.html]

index.html
<!DOCTYPE html>
<html lang="en">

<head>
    <title>Essential JS 2</title>
    <meta charset="utf-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0, user-scalable=no" />
    <meta name="description" content="Essential JS 2" />
    <meta name="author" content="Syncfusion" />
    <link rel="shortcut icon" href="resources/favicon.ico" />
    <link href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css" rel="stylesheet" />
</head>

<body>
    <div>
        <!--element which is going to render-->
        <input id="element" type="checkbox"/>
    </div>

</body>

</html>

Import the CheckBox component in your app.ts file and initialize it to #element as shown in the following.

[src/app/app.ts]

app.ts
import { CheckBox } from '@syncfusion/ej2-buttons';

// Initialize CheckBox component.
let checkbox: CheckBox = new CheckBox({ label: 'Default' });

// Render initialized CheckBox.
checkbox.appendTo('#element');

Run the application

Run the application in the browser using the following command:

npm start

The following example shows a basic CheckBox component.

index.ts
index.html
styles.css
import { CheckBox } from '@syncfusion/ej2-buttons';
import { enableRipple } from '@syncfusion/ej2-base';

enableRipple(true);

// Initialize CheckBox component.
let checkbox: CheckBox = new CheckBox({ label: 'Default' });

// Render initialized CheckBox.
checkbox.appendTo('#element');
<!DOCTYPE html>
<html lang="en">

<head>
    <title>EJ2 CheckBox</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="https://cdn.syncfusion.com/ej2/28.1.33/ej2-base/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/28.1.33/ej2-buttons/styles/material.css" rel="stylesheet" />
    <link href="styles.css" rel="stylesheet" />
    <script src="https://cdnjs.cloudflare.com/ajax/libs/systemjs/0.19.38/system.js"></script>
    <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'>
        <input type='checkbox' id='element'/>
    </div>
</body>

</html>
#container {
    visibility: hidden;
}

#loader {
  color: #008cff;
  height: 40px;
  width: 30%;
  position: absolute;
  top: 45%;
  left: 45%;
}

.e-checkbox-wrapper {
  margin-top: 18px;
}

Change the CheckBox state

The Essential JS 2 CheckBox contains 3 different states visually, they are:

Checked
Unchecked
Indeterminate

The CheckBox checked property is used to handle the checked and unchecked state. In checked state a tick mark will be added to the visualization of CheckBox.

Indeterminate

The CheckBox indeterminate state can be set through indeterminate property. CheckBox indeterminate state masks the real value of CheckBox visually. The Checkbox cannot be changed to indeterminate state through the user interface, this state can be achieved only through the property.

index.ts
index.html
styles.css
import { CheckBox } from '@syncfusion/ej2-buttons';
import { enableRipple } from '@syncfusion/ej2-base';

enableRipple(true);

//checked state.
let checkbox: CheckBox = new CheckBox({ label: 'Checked State', checked: true });
checkbox.appendTo('#checkbox1');

//unchecked state.
checkbox = new CheckBox({ label: 'Unchecked State' });
checkbox.appendTo('#checkbox2');

//indeterminate state.
checkbox = new CheckBox({ label: 'Indeterminate State', indeterminate: true });
checkbox.appendTo('#checkbox3');
<!DOCTYPE html>
<html lang="en">

<head>
    <title>EJ2 CheckBox</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="https://cdn.syncfusion.com/ej2/28.1.33/ej2-base/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/28.1.33/ej2-buttons/styles/material.css" rel="stylesheet" />
    <link href="styles.css" rel="stylesheet" />
    <script src="https://cdnjs.cloudflare.com/ajax/libs/systemjs/0.19.38/system.js"></script>
    <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'>
        <ul>
            <li><input type="checkbox" id="checkbox1" /></li>
            <li><input type="checkbox" id="checkbox2" /></li>
            <li><input type="checkbox" id="checkbox3" /></li>
        </ul>
    </div>
</body>

</html>
#container {
    visibility: hidden;
}

#loader {
  color: #008cff;
  height: 40px;
  width: 30%;
  position: absolute;
  top: 45%;
  left: 45%;
}

.e-checkbox-wrapper {
  margin-top: 18px;
}

li {
  list-style: none;
}