Ember.js Ember.Templates.helpers unbound() Method

Ember.js is an open-source JavaScript framework used for developing large client-side web applications which is based on Model-View-Controller (MVC) architecture. Ember.js is one of the most widely used front-end application frameworks. It is made to speed up development and increase productivity. Currently, it is utilized by a large number of websites, including Square, Discourse, Groupon, Linked In, Live Nation, Twitch, and Chipotle.

The unbound() method is used to disconnect the one-way binding of a property at the moment of rendering. 

Syntax:

{{ unbound val }}

Property: 

• val: It is the value whose value we want to disconnect.

Return Value: It returns the unbound value.

Steps to Install and Run Ember.js:

Step 1: To run the following examples you will need to have an ember project with you. To create one, you will need to install ember-cli first. Write the below code in the terminal:

npm install ember-cli

Step 2: Now you can create the project by typing in the following piece of code:

ember new <project-name> --lang en

To start the server, type:

ember serve

Example 1: Type the following code to generate the route for this example:

ember generate route unbound1

app/components/list2.js

Javascript

import Component from '@glimmer/component';
import { action, set } from '@ember/object';
import { tracked } from '@glimmer/tracking';
import Ember from 'ember';

export default class ListComponent extends Component {
    @tracked
    value = 'GeeksforGeeks';
    @action
    change(data) {
        this.value = "GFG";
    }
}

app/components/list2.hbs

HTML

<h2>{{unbound this.value}} is not changeable.</h2>
<h2>{{this.value}} is changeable.</h2>

<input type="button"
    id="set-code"
    value="Change value"
    {{action 'change' 'GFG'}}/>

app/templates/unbound1.hbs

HTML

{{page-title "List2"}}
<List2 @value={{ this.val }}>
</List2>

Output:

Ember.js Ember.Templates.helpers unbound() Method

Example 2: Type the following code to generate the route for this example:

ember generate route unbound2

app/components/arr2.js

Javascript

import Component from '@glimmer/component';
import { tracked } from '@glimmer/tracking';
import { action } from '@ember/object';
import { mapBy } from '@ember/object';

export default class extends Component {
    @tracked
    value = 'name';

    @tracked
    value2 = 'c++';
    student = [
        {
            name: 'Sam Snehil',
            age: 21,
            skill: 'Python',
        },
        {
            name: 'Satyam Sahu',
            age: 23,
            skill: 'JavaScript',
        },
        {
            name: 'Sohan Argrwal',
            age: 25,
            skill: 'Html',
        },
        {
            name: 'Sreya Sarma',
            age: 19,
            skill: 'PHP',
        },
        {
            name: 'Satyam Sahu',
            skill: 'Angular',
        },
    ];

    @action
    print(data1, data2) {
        this.student.setEach(data1, data2);
    }
}

app/components/arr2.hbs

HTML

{{yield}}
<table>
    <tr>
        <th>Name</th>
        <th>Age</th>
        <th>skill</th>
    </tr>
      {{#each this.student as |detail|}}

    {{#if detail.age}}
            <tr>
            <td>{{unbound (get detail 'name')}}</td>
            <td>{{get detail 'age'}}</td>
            <td>{{get detail 'skill'}}</td>
        </tr>
    {{else}}
    <tr>
            <td>{{unbound (get detail 'name')}}</td>
            <td>{{18}}</td>
            <td>{{get detail 'skill'}}</td>
        </tr>
    {{/if}}
    {{/each}}
</table>
<br/>
{{textarea value=this.value}}

{{textarea value=this.value2}}
<br/>
<input type="button"
    id="set-code"
    value="Update Student details"
    {{action 'print' this.value this.value2}}/>

app/templates/unbound2.hbs

HTML

<Arr2>
    <h1>
        List of Student :
    </h1>
</Arr2>
{{outlet}}

Output:

Ember.js Ember.Templates.helpers unbound() Method

Reference: https://api.emberjs.com/ember/4.6/classes/Ember.Templates.helpers/methods/unbound?anchor=unbound