Ember.js ArrayProxy lastIndexOf() 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 lastIndexOf() method is used to get the index of the given object’s last occurrence.

Syntax:

lastIndexOf( object, startAt );

Parameters:

• object: It is the object which index we want.
• startAt: It is the starting location to search.

Return Value: The last index of the object in an array or -1 if not found.

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

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 lastIndexOf1

app/routes/lastIndexOf1.js

import Route from '@ember/routing/route';

export default class ListRoute extends Route {
    list = [1, 2, 3, 5, 6, 2, 1, 7, 8, 9, 8];
    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/lastIndexOf1.js

import Ember from 'ember';
import { lastIndexOf, includes, addObject, clear }
    from '@ember/array';

export default Ember.Controller.extend({
    actions: {
        insertItem(item) {
            this.list.addObject(item);
        },
        clearList() {
            this.list.clear();
        },
        contains(item) {
            let res = this.list.includes(JSON.parse(item));
            alert(`The list ${res
                ? '' : 'does not'} contains ${item}`);
        },
        checkLastIndex(item) {
            let res = this.list.lastIndexOf(JSON.parse(item));
            alert(res);
        },
    },
});

app/templates/lastIndexOf1.hbs

{{page-title "LastIndexOf"}}
<h3>Here is a list of Items: </h3>
<ul>
    {{#each @model as |i|}}
        <li>{{i}}</li>
    {{/each}}
</ul>
<br/>
<div>
    <label>Enter Item: </label>
    {{input value=this.item2}}
</div>
<div>
    <input
        type="button"
        id="contains-item"
        value="Contains?"
        {{action "contains" this.item2}}
    />
</div>
<br/>
<div>
    <input
        type="button"
        id="check-item"
        value="Check Last Index"
        {{action "checkLastIndex" this.item2}}
    />
</div>
<br />
<div>
    <label>Enter Item: </label>
    {{input value=this.item}}
</div>
<div>
    <input
        type="button"
        id="insert-item"
        value="Insert Item"
        {{action "insertItem" this.item }}
    />
</div>
<br />
<input type="button" id="clear-items"
    value="Clear"
    {{action "clearList"}} />
{{outlet}}

Output: Visit localhost:4200/lastIndexOf1 to view the output

Ember.js ArrayProxy lastIndexOf method

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

ember generate route lastIndexOf2

app/routes/lastIndexOf2.js

import Route from '@ember/routing/route';

export default class PartyRoute extends Route {
    partyItems = [
        'Oxygen',
        'Source Code',
        'Infine',
        'Tenet',
        'SpiderHead',
        'The Thing',
        'A Quiet Place',
        'The Invisible Man',
        'Looper',
        'Ad Astra'
    ];
  temp = [
        'Shutter Island',
        'Matrix',
        'Avatar',
        'Fantastic Beast',
        'Avengers',
        'Fantastic four',
        'HulK',
        'Superman',
        'Spiderman',
        'The Batman'
    ];
    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);
    controller.set('temp', this.temp);
    }
}

app/controllers/lastIndexOf2.js

import Ember from 'ember';
import { pushObject, pushObjects, lastIndexOf, includes }
    from '@ember/array';

export default Ember.Controller.extend({
    actions: {
        insertItem(item) {
            this.partyItems.pushObject(item);
        },
        push_item(data) {
            this.partyItems.pushObjects(data);
        },
        contains(item) {
            let res = this.partyItems.includes(item);
            alert(`The List ${res
                ? '' : 'does not'} contains ${item}`);
        },
        checkLastindex(item) {
            let res = this.partyItems.lastIndexOf(item);
            alert(res);
        },
    },
});

app/templates/lastIndexOf2.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>
    <input
        type="button"
        id="insert-item"
        value="Insert Item"
        {{action "insertItem" this.item}}
    />
</div>
<br />
<div>
    <label>Enter Item: </label>
    {{input value=this.item2}}
</div>
<div>
    <input
        type="button"
        id="contains-item"
        value="Contains?"
        {{action "contains" this.item2}}
    />
</div>
<br/>
<div>
    <input
        type="button"
        id="get-item"
        value="Get Last Index"
        {{action "checkLastindex" this.item2}}
    />
</div>
<br />
<input
        type="button"
        id="contains-item"
        value="Add Movies"
        {{action "push_item" this.temp}}
    />
{{outlet}}

Output: Visit localhost:4200/lastIndexOf2 to view the output

Ember.js ArrayProxy lastIndexOf method

Reference: https://api.emberjs.com/ember/4.6/classes/ArrayProxy/methods/lastIndexOf?anchor=lastIndexOf