Ember.js ArrayProxy objectsAt() 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 objectsAt() method is used to get the objects at the given indexes.

Syntax:

objectsAt( indexes );

Parameters:

• indexes: It is the array of index items to return.

Steps to Install and Run Ember.js:

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 objectsAt1

app/routes/objectsAt1.js

import Route from '@ember/routing/route';
import { classify, w } from '@ember/string';
import { objectsAt } from '@ember/array';

export default class LanguagesRoute extends Route {
    name = `Hindi Korean Marathi Telugu Portuguese
        Turkish Bengali Spanish`;
    num = `343.9 81.7 83.1 82.0 232.4 82.3 233.7 474`;

    languages = [];

    initLanguages() {
        this.languages = [];
        this.name = w(this.name);
        this.num = w(this.num);
        for (let i = 0; i < this.name.length; i++) {
            let obj = new Object();
            obj['name'] = classify(this.name[i]);
            obj['num'] = this.num[i];
            this.languages.pushObject(obj);
        }
    }
    temp1;
    convert(string) {
        this.item = string.split(",").map((item) => item.trim());
        return this.item;
    }

    model() {
        this.initLanguages();
        return this.languages;
    }
    setupController(controller, model) {
        super.setupController(controller, model);
        controller.set('languages', this.languages);
        controller.set('temp1', this.temp1);
        controller.set('convert', this.convert)
    }
}

app/controllers/objectsAt1.js

import Ember from 'ember';
import { objectsAt } from '@ember/array';

export default Ember.Controller.extend({
    actions: {
        get_Name() {
            let ans = this.languages.mapBy('name');
            alert(ans.join('\n'));
        },
        get_most() {
            let temp = 0;
            let tempItems = this.languages.map((item) =>
                temp < JSON.parse(item.num) ? temp = item.name : temp);
            alert(temp);

        },
        remove() {
            this.languages.popObject();
        },
        check_item(idx) {
            let temp = this.languages.objectAt(JSON.parse(idx));
            alert(temp.name)
        },
        check_items(idx) {
            idx = this.convert(idx);
            let temp = this.languages.objectsAt(idx);
            let ans = temp.mapBy('name')
            alert(ans.join('\n'))
        },
    },
});

app/templates/objectsAt1.hbs

{{page-title "objectsAt"}}
<h2>Spoken Languages in the World</h2>
<table style="border: 2px solid black;padding: 30px;">
    <tr>
        <th>Language</th>
        <th>Native Speakers (in Millions)</th>
    </tr>
        {{#each @model as |language|}}
            <tr>
                <td>{{language.name}}</td>
                <td>{{language.num}}</td>
            </tr>
        {{/each}}
</table>
<br /><br />
<div>
    <label>Enter index: </label>
    {{input value=this.temp}}
</div>
<input
    type="button"
    id="increase-pocket-money"
    value="Get Language at Index"
    {{action "check_item" this.temp}}
/>
<br /><br />
<div>
    <label>Enter indexs: </label>
    {{input value=this.temp2}}
</div>
<input
    type="button"
    id="check-atIndex"
    value="Check at indexes"
    {{action "check_items" this.temp2}}
/>
<br/>
<br />
<div>
    <input
        type="button"
        id="check-fruit"
        value="Check Most speaking Language"
        {{action "get_most"}}
    />
</div>
<br />
<div>
    <input
        type="button"
        id="remove-item"
        value="Remove Last Element"
        {{action "remove"}}
    />
</div>
<br />
<div>
    <input
        type="button"
        id="show-lang"
        value="Show Language"
        {{action "get_Name"}}
    />
</div>
{{outlet}}

Output: Visit localhost:4200/objectsAt1 to view the output

Ember.js ArrayProxy objectsAt method

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

ember generate route objectsAt2

app/routes/objectsAt2.js

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

export default class StudentsRoute extends Route {
    students = [
        {
            name: "Aaush Somankar",
            gender: "M",
            class: 12,
            grade: "A",
        },
        {
            name: "Aman Prakash",
            gender: "M",
            class: 10,
            grade: "A",
        },
        {
            name: "Siya guru",
            gender: "F",
            class: 11,
            grade: "B",
        },
        {
            name: "Ramesh verma",
            gender: "M",
            class: 10,
            grade: "A",
        },
        {
            name: "Esnoor",
            gender: "M",
            class: 9,
            grade: "F",
        },
        {
            name: "Balit",
            gender: "M",
            class: 10,
            grade: "A",
        },
        {
            name: "Dora",
            gender: "F",
            class: 12,
            grade: "F",
        },
        {
            name: "Lalu",
            gender: "F",
            class: 8,
            grade: "A",
        },
        {
            name: "Pokhraj",
            gender: "M",
            class: 11,
            grade: "F",
        },
        {
            name: "Citu",
            gender: "M",
            class: 8,
            grade: "C",
        },
        {
            name: "Rahul",
            gender: "M",
            class: 9,
            grade: "A",

        },
        {
            name: "Ram",
            gender: "M",
            class: 12,
            grade: "A",
        },
        {
            name: "Priti",
            gender: "F",
            class: 9,
            grade: "F",
        },
        {
            name: "Flip",
            gender: "M",
            class: 9,
            grade: "B",
        },
        {
            name: "Sita",
            gender: "F",
            class: 8,
            grade: "A",
        },
        {
            name: "Aashray",
            gender: "M",
            class: 12,
            grade: "C",
        },
        {
            name: "Suneel",
            gender: "M",
            class: 8,
            grade: "C",
        },
    ];
    convert(string) {
        this.item = string.split(",").map((item) => item.trim());
        return this.item;
    }

    model() {
        return this.students;
    }
    setupController(controller, model) {
        super.setupController(controller, model);
        controller.set("students", this.students);
        controller.set("convert", this.convert);
        controller.set("item", this.item);
    }
}

app/controllers/objectsAt2.js

import Ember from "ember";

export default Ember.Controller.extend({
    actions: {
        getAllNames() {
            let res = this.students.mapBy('name');
            alert(res.join('\n'));
        },
        allPass() {
            let temp = '';
            let tempItems = this.students.map((item) =>
                item.grade == 'F' ? temp += item.name + '\n' : temp);
            alert(temp);

        },
        remove() {
            this.students.popObject();
        },
        check_item(idx) {
            let temp = this.students.objectAt(JSON.parse(idx));
            alert(temp.name)
        },
        check_items(idx) {
            idx = this.convert(idx);
            let temp = this.students.objectsAt(idx);
            let ans = temp.mapBy('name')
            alert(ans.join('\n'))
        },
    },
});

app/templates/objectsAt2.hbs

{{page-title "objectsAt"}}
<h3>List of Students: </h3>

<table>
    <tr>
        <th>Name</th>
        <th>Class</th>
        <th>Gender</th>
        <th>Grade</th>
    </tr>
    {{#each @model as |student|}}
    <tr>
        <td>{{student.name}}</td>
        <td>{{student.class}}</td>
        <td>{{student.gender}}</td>
        <td>{{student.grade}}</td>
    </tr>
    {{/each}}
</table>
<br /><br />
<input
    type="button"
    id="get-all"
    value="Get All Names"
    {{action "getAllNames"}}
/>
<br /><br />
<input
    type="button"
    id="all-pass"
    value="Did Everyone Pass?"
    {{action "allPass"}}
/>

<br /><br />
<div>
    <label>Enter index: </label>
    {{input value=this.temp}}
</div>
<input
    type="button"
    id="increase-pocket-money"
    value="Get Person at Index"
    {{action "check_item" this.temp}}
/>
<br /><br />
<div>
    <label>Enter indexs: </label>
    {{input value=this.temp2}}
</div>
<input
    type="button"
    id="check-atIndex"
    value="Check at indexes"
    {{action "check_items" this.temp2}}
/>
<br /><br />
<input
    type="button"
    id="remove-last"
    value="Remvoe Last Student"
    {{action "remove"}}
/>
{{outlet}}

Output: Visit localhost:4200/objectsAt2 to view the output

Ember.js ArrayProxy objectsAt method

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