Ember.js EmberArray 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 fetch items for the given array of indices.

Syntax:

objectsAt(indexes)

Parameter:

• indexes: The indexes for which an object needs to be fetched.

Returns: Returned items.

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 party

app/routes/party.js

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

export default class PartyRoute extends Route {
    partyItems = [
        "Digital Camera",
        "Jugs, cups & straws",
        "Balloons",
        "Scissors",
        "Cold Drink",
        "Table Confetti",
        "Party Hats",
        "Wine",
        "Napkins",
        "Party Plates",
        "Speakers",
        "Music System",
        "Cups",
    ];
    itemString;
    itemList;
    start;
    end;
    helper(itemString) {
        this.itemList = itemString.split(",");
        for (let i = 0; i < this.itemList.length; i++)
            this.itemList[i] = this.itemList[i].trim();
        return this.itemList;
    }
    model() {
        return this.partyItems;
    }
    setupController(controller, model) {
        this._super(controller, model);
        controller.set("helper", this.helper);
        controller.set("partyItems", this.partyItems);
        controller.set("itemString", this.itemString);
        controller.set("itemList", this.itemList);
        controller.set("start", this.start);
        controller.set("end", this.end);
    }
}

app/controllers/party.js

import Ember from "ember";
import {
    objectsAt,
    removeObject,
    removeObjects,
    slice,
    reverseObjects,
    setObjects,
    reject,
} from "@ember/array";

export default Ember.Controller.extend({
    actions: {
        getItems(itemString) {
            this.itemList = this.helper(itemString);
            for (let i = 0; i < this.itemList.length; i++)
                this.itemList[i] =
                parseInt(this.itemList[i]);
            let tempItems =
                this.partyItems.objectsAt(this.itemList);
            let str = "";
            for (let i = 0; i < tempItems.length; i++)
                str += tempItems[i] + "\n";
            alert(str);
        },
        removeItems(itemString) {
            this.itemList = this.helper(itemString);
            if (this.itemList.length == 1)
                this.partyItems.removeObject(
                    this.itemList[0]);
            else this.partyItems.removeObjects(
                this.itemList);
            this.set("itemString", "");
        },
        sliceItems(start, end) {
            let tempItems = this.partyItems.slice(start, end);
            let str = "";
            for (let i = 0; i < tempItems.length; i++)
                str += tempItems[i] + "\n";
            alert(str);
        },
        reverseItems() {
            this.set("partyItems",
            this.partyItems.reverseObjects());
        },
        replaceItems(itemString) {
            this.partyItems.setObjects(
            this.helper(itemString));
        },
        findMultiwordItems() {
            let reqItem = this.partyItems.reject(
                (item) => item.split(" ").toArray().length == 1
            );
            alert(reqItem);
        },
    },
});

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 Items: </label>
      {{input value=this.itemString}}
</div>
<div>
    <input
        type="button"
        id="remove-item"
        value="Remove Items"
        {{action "removeItems" this.itemString}}
      />
</div>
<br /><br />
<div>
    <label>Enter Start Index: </label>
      {{input value=this.start}}
</div>
<div>
    <label>Enter End Index: </label>
      {{input value=this.end}}
</div>
<div>
    <input
        type="button"
        id="slice"
        value="Slice"
        {{action "sliceItems" this.start this.end}}
      />
</div>
<br /><br />
<div>
    <label>Enter Indices: </label>
      {{input value=this.itemString}}
</div>
<div>
    <input
        type="button"
        id="get-item"
        value="Get Items"
        {{action "getItems" this.itemString}}
      />
</div>
<br /><br />
<div>
    <label>Enter Items: </label>
      {{input value=this.itemString}}
</div>
<div>
    <input
        type="button"
        id="replace-item"
        value="Replace Items"
        {{action "replaceItems" this.itemString}}
      />
</div>
<br /><br />
<input
    type="button"
      id="reverse-items"
      value="Reverse"
      {{action "reverseItems"}}
/>
<br /><br />
<input
    type="button"
      id="find-items"
      value="Find"
      {{action "findMultiwordItems"}}
/>
{{outlet}}

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

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

ember generate route movie

app/routes/movie.js

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

export default class MovieRoute extends Route {
    movies = [
        "The Shawshank Redemption",
        "The Godfather",
        "The Dark Knight",
        "Schindler's List",
        "The Godfather Part II",
        "12 Angry Men",
        "Pulp Fiction ",
        "Raging Bull",
        "Parasite",
        "Se7en",
        "3 Idiots",
        "Forrest Gump",
        "The Green Mile",
    ];
    itemString;
    itemList;
    helper(itemString) {
        this.itemList = itemString.split(",");
        for (let i = 0; i < this.itemList.length; i++)
            this.itemList[i] = this.itemList[i].trim();
        return this.itemList;
    }
    model() {
        return this.movies;
    }
    setupController(controller, model) {
        super.setupController(controller, model);
        controller.set("helper", this.helper);
        controller.set("movies", this.movies);
        controller.set("itemString", this.itemString);
        controller.set("itemList", this.itemList);
    }
}

app/controllers/movie.js

import Ember from "ember";
import {
    objectsAt,
    removeObject,
    removeObjects,
    setObjects,
    reject,
} from "@ember/array";

export default Ember.Controller.extend({
    actions: {
        getItems(itemString) {
            this.itemList = this.helper(itemString);
            for (let i = 0; i < this.itemList.length; i++)
                this.itemList[i] =
                    parseInt(this.itemList[i]);
            let tempItems = this.movies.objectsAt
                (this.itemList);
            let str = "";
            for (let i = 0; i < tempItems.length; i++)
                str += tempItems[i] + "\n";
            alert(str);
        },
        removeItems(itemString) {
            this.itemList = this.helper(itemString);
            if (this.itemList.length == 1)
                this.movies.removeObject(
                    this.itemList[0]);
            else this.movies.removeObjects(
                this.itemList);
            this.set("itemString", "");
        },
        replaceItems(itemString) {
            this.movies.setObjects(this.helper(
                itemString));
        },
        findSingleWordItems() {
            let reqItem = this.movies.reject(
                (item) =>
                    item.split(" ").toArray().length > 1
            );
            alert(reqItem);
        },
    },
});

app/template/movie.hbs

{{page-title "Movie"}}
<h3>Here is a list of Movies: </h3>
<ul>
    {{#each @model as |movie|}}
        <li>{{movie}}</li>
      {{/each}}
</ul>
<br /><br />
<div>
    <label>Enter Movies: </label>
      {{input value=this.itemString}}
</div>
<div>
    <input
        type="button"
        id="remove-item"
        value="Remove Movie"
        {{action "removeItems" this.itemString}}
      />
</div>
<br /><br />
<div>
    <label>Enter Indices: </label>
      {{input value=this.itemString}}
</div>
<div>
    <input
        type="button"
        id="get-item"
        value="Get Movies"
        {{action "getItems" this.itemString}}
      />
</div>
<br /><br />
<div>
    <label>Enter Movies: </label>
      {{input value=this.itemString}}
</div>
<div>
    <input
        type="button"
        id="replace-item"
        value="Replace Movies"
        {{action "replaceItems" this.itemString}}
      />
</div>
<br /><br />
<input
    type="button"
      id="find-items"
      value="Find"
      {{action "findSingleWordItems"}}
/>
{{outlet}}

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

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