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Ember.js MutableArray indexOf() Method

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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 indexOf() method is used to find the index of a given object in the array.

Syntax:

indexOf(obj,startAt)

Parameters:

  • obj: The object to find.
  • startAt: The index from where to start the search.

Returns: It returns the index or -1 if object is not present.

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 list

app/routes/list.js




import Route from '@ember/routing/route';
  
export default class ListRoute extends Route {
    list = ['a', 'a', 'v', 'c', 'c', 'a', 'd'
        'q', 'b', 'z', 'a'];
    item;
    idx;
    model() {
        return this.list;
    }
    setupController(controller, model) {
        super.setupController(controller, model);
        controller.set('list', this.list);
        controller.set('item', this.item);
        controller.set('idx', this.idx);
    }
}


app/controllers/list.js




import Ember from 'ember';
import { clear, insertAt, indexOf, lastIndexOf,
    includes } from '@ember/array';
  
export default Ember.Controller.extend({
    actions: {
        insertItem(item, idx) {
            this.list.insertAt(idx, item);
        },
        getLastIndex(item) {
            let res = this.list.lastIndexOf(item);
            alert(res);
        },
        getFirstIndex(item) {
            let res = this.list.indexOf(item);
            alert(res);
        },
        clearList() {
            this.list.clear();
        },
        contains(item) {
            let res = this.list.includes(item);
            alert(`The list ${res ? '' : 'does not'}
            contains ${item}`);
        },
    },
});


app/template/list.hbs




{{page-title "List"}}
<h3>Here is a list of Items: </h3>
<ul>
    {{#each @model as |i|}}
        <li>{{i}}</li>
    {{/each}}
</ul>
<br /><br />
<div>
    <label>Enter Item: </label>
    {{input value=this.item}}
</div>
<div>
    <label>Enter Index: </label>
    {{input value=this.idx}}
</div>
<div>
    <input
        type="button"
        id="insert-item"
        value="Insert Item"
        {{action "insertItem" this.item this.idx}}
  />
</div>
<br /><br />
<div>
    <label>Enter Item: </label>
    {{input value=this.item}}
</div>
<div>
    <input
        type="button"
        id="first-index-item"
        value="Get First Index"
        {{action "getFirstIndex" this.item}}
  />
</div>
<div>
    <input
        type="button"
        id="last-index-item"
        value="Get Last Index"
        {{action "getLastIndex" this.item}}
  />
</div>
<div>
    <input
        type="button"
        id="contains-item"
        value="Contains?"
        {{action "contains" this.item}}
  />
</div>
<br /><br />
<input type="button" id="clear-items" 
    value="Clear" {{action "clearList"}} />
{{outlet}}


Output: Visit localhost:4200/list to view the output

 

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

ember generate route party

app/routes/party.js




import Route from '@ember/routing/route';
  
export default class PartyRoute extends Route {
    partyItems = [
        'Digital Camera',
        'Jugs, cups & straws',
        'Cold Drink',
        'Balloons',
        'Scissors',
        'Wine',
        'Cold Drink',
        'Table Confetti',
        'Party Hats',
        'Wine',
        'Napkins',
        'Party Plates',
        'Speakers',
        'Wine',
        'Music System',
        'Cold Drink',
        'Cups',
    ];
    item;
    idx;
    model() {
        return this.partyItems;
    }
    setupController(controller, model) {
        super.setupController(controller, model);
        controller.set('partyItems', this.partyItems);
        controller.set('item', this.item);
        controller.set('idx', this.idx);
    }
}


app/controllers/party.js




import Ember from 'ember';
import { insertAt, indexOf, lastIndexOf, 
    includes } from '@ember/array';
  
export default Ember.Controller.extend({
    actions: {
        insertItem(item, idx) {
            this.partyItems.insertAt(idx, item);
        },
        getLastIndex(item) {
            let res = this.partyItems.lastIndexOf(item);
            alert(res);
        },
        getFirstIndex(item) {
            let res = this.partyItems.indexOf(item);
            alert(res);
        },
        clearpartyItems() {
            this.partyItems.clear();
        },
        contains(item) {
            let res = this.partyItems.includes(item);
            alert(`The partyItems ${res ? ''
            'does not'} contains ${item}`);
        },
    },
});


app/template/party.hbs




{{page-title "Party"}}
<h3>Here is a list of items: </h3>
<ul>
    {{#each @model as |party|}}
    <li>{{party}}</li>
    {{/each}}
</ul>
<<br/><br/>
<div>
    <label>Enter Item: </label>
    {{input value=this.item}}
</div>
<div>
    <label>Enter Index: </label>
    {{input value=this.idx}}
</div>
<div>
    <input type="button" id="insert-item" 
        value="Insert Item"
        {{action 'insertItem' this.item this.idx}}/>
</div>
<br/><br/>
<div>
    <label>Enter Item: </label>
    {{input value=this.item}}
</div>
<div>
    <input type="button" id="first-index-item" 
        value="Get First Index" 
        {{action 'getFirstIndex' this.item}}/>
</div>
<div>
    <input type="button" id="last-index-item" 
        value="Get Last Index" 
        {{action 'getLastIndex' this.item}}/>
</div>
<div>
    <input type="button" id="contains-item" 
        value="Contains?" 
        {{action 'contains' this.item}}/>
</div>
<br/><br/>
{{outlet}}


Output: Visit localhost:4200/party to view the output

 

Reference: https://api.emberjs.com/ember/4.4/classes/MutableArray/methods



Last Updated : 31 Aug, 2022
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