Getting started with EJ2 TypeScript DropDown Tree control

24 Jul 20265 minutes to read

This section explains the steps to create a simple DropDown Tree and demonstrates the basic usage of the DropDown Tree component using the Essential® JS 2 quickstart seed repository. This seed repository is pre-configured with the Essential® JS 2 package.

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.

Prerequisites

Ensure the following tools are installed on your machine:

Set up the development environment

Clone the Syncfusion® TypeScript (Essential® JS 2) quickstart project from GitHub in the command prompt:

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

Navigate to the project folder in the command prompt:

cd ej2-quickstart

Install Syncfusion® TypeScript DropDown Tree packages

Use the following command to install the @syncfusion/ej2-dropdowns package:

npm install @syncfusion/ej2-dropdowns

Install the required npm packages:

npm install

For more information about individual packages and alternative installation methods, see the installation guide.

Import Syncfusion® CSS styles

Syncfusion® TypeScript controls provide built-in themes, which are available from the npm theme packages. Additionally, themes can be loaded via CDN or customized using the Theme Studio. For more information, refer to the themes documentation.

The quickstart application is preconfigured to use the Fluent2 theme. To install the Fluent2 theme package, use the following command:

npm install @syncfusion/ej2-fluent2-theme --save

The required styles are imported in the ~/src/styles/styles.css file, as shown below:

@import "../../node_modules/@syncfusion/ej2-fluent2-theme/styles/drop-down-tree/index.css";

Learn more about built-in themes and individual control CSS references.

Add Syncfusion® DropDown Tree control to the application

Add the HTML input element that needs to be initialized as a Dropdown Tree in index.html.

[src/index.html]

<!DOCTYPE html>
<html lang="en">
<head>
    <title>Essential JS 2 Dropdown Tree control</title>
    <meta charset="utf-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0, user-scalable=no" />
</head>

<body>
    <div id='container' style="margin:0 auto; width:300px;">
        <!--element which is going to render the Dropdown Tree-->
        <input type="text" tabindex="1" id='ddTreeElement' />
    </div>
</body>

</html>

The Dropdown Tree control can load the data either from local data sources or remote data services. This can be done using the dataSource property that is a member of the fields property. The dataSource property supports array of JavaScript objects and DataManager. Here, an array of JSON values is passed to the Dropdown Tree control.

Now, import the Dropdown Tree control to your app.ts and initialize it to the element #ddTreeElement as shown below.

[src/app/app.ts]

import { DropDownTree } from '@syncfusion/ej2-dropdowns';

//define the array of JSON
let data: { [key: string]: Object }[] = [
    {
        nodeId: '01', nodeText: 'Music',
        nodeChild: [
            { nodeId: '01-01', nodeText: 'Gouttes.mp3' }
        ]
    },
    {
        nodeId: '02', nodeText: 'Videos', expanded: true,
        nodeChild: [
            { nodeId: '02-01', nodeText: 'Naturals.mp4' },
            { nodeId: '02-02', nodeText: 'Wild.mpeg' },
        ]
    },
    {
        nodeId: '03', nodeText: 'Documents',
        nodeChild: [
            { nodeId: '03-01', nodeText: 'Environment Pollution.docx' },
            { nodeId: '03-02', nodeText: 'Global Water, Sanitation, & Hygiene.docx' },
            { nodeId: '03-03', nodeText: 'Global Warming.ppt' },
            { nodeId: '03-04', nodeText: 'Social Network.pdf' },
            { nodeId: '03-05', nodeText: 'Youth Empowerment.pdf' },
        ]
    },
];

// initialize Dropdown Tree control
let DropDownTreeObject: DropDownTree = new DropDownTree({
    //binding data source through fields property
    fields: { dataSource: data, value: 'nodeId', text: 'nodeText', child: 'nodeChild' }
});

// render initialized Dropdown Tree
DropDownTreeObject.appendTo('#ddTreeElement');

Run the application

Now, run the application in the browser using the following command.

npm start