Ember.js ArrayProxy Class

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.

ArrayProxy Class:

The ArrayProxy class acts as a wrapper object which forwards all requests to any other object that implements Array and/or MutableArray. The ability to change out the underlying array is advantageous in a variety of binding use cases, as well as in other situations.

Methods: The following is the list of methods for this class.

• addObject: This method is used to push an object onto the end of the array if the object is not a present array.
• addObjects: This method is used to add a number of objects to the array.
• addObserver: This method is used to register an observer for a property.
• any: This method is used to check if there are any objects in the target that matches the condition laid by the callback function.
• cacheFor: This method is used to get the cached value for an already computed property if it exists.
• clear: This method removes all the elements in the array
• compact: This method is used to make a copy of an array without null and undefined elements.
• decrementProperty: This method is used to set the value of the property to the current value minus some amount.
• destroy: This method destroys an object by setting the isDestroyed flag and deleting its metadata.
• every: This method is used to check if all objects in the array pass a specific callback function.
• filter: This method is used to filter objects in the array according to a specific condition.
• filterBy: This method is used to return an array with just the items with the matched property.
• find: This method is used to find elements that match the given callback function.
• findBy: This method is to get the first item with a property matching the passed value.
• forEach: This method is used to run a function on every item of the array.
• get: This method is used to retrieve the value of a property from the object.
• getEach: This method is used to get all values in the array for a given key.
• getProperties: This method is used to get the value of multiple properties at once.
• includes: This method is used to check if a given object is present in the array or not.
• incrementProperty: This method is used to set the value of the property to the current value plus some amount.
• indexOf: This method is used to find the index of a given object in the array.
• init: This method is called when objects are instantiated.
• insertAt: This method is used to insert an object in a specific position in the array.
• invoke: This method is used to call the passed method on every object in the receiver that implements it.
• isAny: This method is used to check if for anyone the element in the array the passed property resolves to the desired value or not.
• isEvery: This method is used to check if, for each element in the array, the passed property resolves to the desired value or not.
• lastIndexOf: This method is used to find the last index of an object in the array.
• map: This method is used to map all items in the array with a specific function.
• mapBy: This method is used to get the value of the named property on all items in the list. 
• notifyPropertyChange: This method alerts the observer system that a property change has taken place.
• objectAt: This method is used to retrieve the object at a given index.
• objectAtContent: This method is used to retrieve the object at the specified index from the content.
• objectsAt: This method is used to fetch items for the given array of indices.
• popObject: This method is used to pop objects from an array.
• pushObject: This method is used to push an object into an array.
• pushObjects: This method is used to push multiple objects into an array.
• reduce: This method is used to combine the values of the array into a single value.
• reject: This method provides a list of all the enumerated elements for which the provided function returns false.
• rejectBy: This method returns an array containing the objects for which the given key's value is false.
• removeAt: This method is used to remove elements on a given index.
• removeObject: This method removes all instances of the object from the array.
• removeObjects: This method removes each supplied item from the given array.
• removeObserver: This method removes any observers you have registered earlier for this object.
• replace: This method is used to replace some of the elements in the array with the given objects.
• replaceContent: This method in fact swaps out the designated objects on the content array.
• reverseObjects: This method reverses the elements in the array.
• set: This method is used to set the key and value to the object.
• setEach: This method, for each member, sets the value of the named property.
• setObjects: This method replaces the receiver's content with the argument's substance.
• setProperties: This method sets a number of properties at once.
• shiftObject: This method shifts nil, if there are no more, or an object from the array's beginning.
• slice: This method is used to return a new array that is a portion of the receiver.
• sortBy: This method is used to sort an array by the specified key.
• toArray: This method just transforms the object into a real array.
• toString: This method is to get the string representation of the object. 
• toggleProperty: This method is used to set the value of the boolean property to the opposite of its current value.
• uniq: This method returns a brand-new array with just unique values in it.
• uniqBy: This method is used to get objects which unique values for the given key.
• unshiftObject: This method is used to add a single object to the start of the array.
• unshiftObjects: This method is used to add objects to the front of the array.
• willDestroy: This method tears down the object.
• without: This method gives back a new array without the given value.

Properties: The following is the list of the properties of this class:

• []: This property is used to get or set the array content.
• arrangedContent: This property defines the array the proxy represents itself as.
• concatenatedProperties: This property specifies the characteristics from the superclass that will be concatenated
• content: This property is used to forward the object property.
• firstObject: This property is used to retrieve the first object of the array.
• isDestroyed: This property is the destroy complete flag.
• isDestroying: This property is the destroy scheduled flag.
• lastObject: This property is used to retrieve the last object of the array.
• length: This property is used to retrieve the length of the array.
• mergedProperties: This property helps to merge the value of the subclass property’s value with the superclass property value of the ember class.

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: In this example, I am going to demonstrate the use of the function sortBy of the class.

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

ember generate route languages

app/routes/languages.js

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

export default class LanguagesRoute extends Route {
    name =
        `mandarin_Chinese spanish english Hindi 
         bengali Portuguese russian japanese 
         western_punjabi yueChinese`;
    num = `929.0 474.7 372.9 343.9 233.7 
       232.4 154.0 125.3 92.7 85.2`;

    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);
        }
    }

    model() {
        this.initLanguages();
        this.languages = this.languages.sortBy('name');
        return this.languages;
    }
}

app/template/languages.js

{{page-title "Languages"}}
<h2>Most Spoken Languages in the World</h2>
<table style="border: 2px solid black;padding: 30px;">
    <tr>
        <th>Language</th>
        <th>Native Speakers (millions)</th>
      </tr>
      {{#each @model as |language|}}
    <tr>
        <td>{{language.name}}</td>
          <td>{{language.num}}</td>
    </tr>
    {{/each}}
</table>
{{outlet}}

Output:

Example 2: In this example, I am going to demonstrate the use of the functions: objectsAt(), removeObject(), removeObjects(), slice(), reverseObjects(), setObjects() and reject().

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:

Reference: https://api.emberjs.com/ember/4.9/classes/ArrayProxy