Ember.js MutableArray indexOf() Method

Last Updated : 31 Aug, 2022

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}}