Getting started in EJ2 TypeScript Drop down tree control

3 Nov 202311 minutes to read

This section explains you about how to create a simple Dropdown Tree control and configure its available functionalities in TypeScript using the Essential JS 2 quickstart.

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 Dropdown Tree control in your application.

|-- @syncfusion/ej2-dropdowns
    |-- @syncfusion/ej2-base
    |-- @syncfusion/ej2-data
    |-- @syncfusion/ej2-inputs
    |-- @syncfusion/ej2-lists
    |-- @syncfusion/ej2-navigations
    |-- @syncfusion/ej2-popups
        |-- @syncfusion/ej2-buttons

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 DropDownTree component, need to import dropdowns and its dependent components styles as given below 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';
@import '../../node_modules/@syncfusion/ej2-navigations/styles/material.css';
@import '../../node_modules/@syncfusion/ej2-inputs/styles/material.css';
@import '../../node_modules/@syncfusion/ej2-popups/styles/material.css';
@import '../../node_modules/@syncfusion/ej2-lists/styles/material.css';
@import '../../node_modules/@syncfusion/ej2-dropdowns/styles/material.css';

Initialize the Dropdown Tree

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" />
    <meta name="description" content="Essential JS 2" />
    <meta name="author" content="Syncfusion" />
    <link href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css" rel="stylesheet" />
</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='ddltreeelement' />
    </div>

</body>

</html>

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

[src/app/app.ts]

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

// initialize Dropdown Tree control
let DropDownTreeObject: DropDownTree = new DropDownTree();

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

Binding data source

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.

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('#ddltreeelement');

Run the application

After completing the configuration required to render a basic Dropdown Tree, run the following command to display the output in your default browser.

npm run start

The following example explains the output in your browser.

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' }
    // set placeholder to Dropdown Tree input element
    placeholder: "Select a Item"
});

// render initialized Dropdown Tree
DropDownTreeObject.appendTo('#ddltreeelement');
<!DOCTYPE html>
<html lang="en">

<head>
    <title>Essential JS 2 DropDownList</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="styles.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/25.1.35/ej2-base/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/25.1.35/ej2-inputs/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/25.1.35/ej2-buttons/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/25.1.35/ej2-lists/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/25.1.35/ej2-navigations/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/25.1.35/ej2-dropdowns/styles/material.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' style="margin:0 auto; width:250px;">
        <input type="text" tabindex="1" id='ddltreeelement' />
    </div>
</body>

</html>