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Getting started in EJ2 TypeScript Check box control

10 Feb 20269 minutes to read

This section explains how to create a simple CheckBox control and configure its available functionalities in TypeScript, using the 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 dependencies are required to use the CheckBox component in your application:

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

Setup 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

Syncfusion® JavaScript controls come with built-in themes, which are available in the installed packages. It’s easy to adapt the Syncfusion® JavaScript controls to match the style of your application by referring to one of the built-in themes.

The quickstart application is preconfigured to use the Material theme in the ~/src/styles/styles.css file, as shown below:

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

You can check out the themes section to know more about built-in themes and CSS reference for individual controls.

Add CheckBox to the project

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

[src/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 with the #element selector as shown below.

[src/app/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.

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/ej2/32.2.3/ej2-base/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/32.2.3/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 manages the checked and unchecked states. When checked, a tick mark appears in the CheckBox visualization.

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.

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/ej2/32.2.3/ej2-base/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/32.2.3/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;
}