Ember.js ArrayProxy removeObserver() Method

Last Updated : 20 Jan, 2023

Ember.js is an open-source JavaScript framework used for developing large client-side web applications which are 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 removeObserver() method of ArrayProxy is a method that is used to remove the registered observer of the object. This method disconnects the key and observer.

Syntax:

this.object.removeObserver( key, target, method, sync );

Parameters:

key: It is the from which the observer will remove.
target: It is an object which is the owner of the key.
method: It is the which is invoked as per observer command.
sync: It specifies whether the observer is async or not.

Return type: Observable.

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 test1

app/routes/test1.js

Javascript

import Route from '@ember/routing/route';
import ArrayProxy from '@ember/object';
import { computed } from '@ember/object';
import Ember from 'ember';
 
const Student = ArrayProxy.extend({
 
    Changed: Ember.observer('marks', function () {
        console.log(`Marks of ${this.name} changed`);
    }),
 
});
 
export default class StudentsRoute extends Route {
    student = Student.create({
        name: 'Arun Verma',
        class: 12,
        Branch: 'Commerce',
        gender: 'M',
        marks: 73,
        mobile: '837483783',
        Roll_No: '1238372',
 
    })
 
    model() {
        return this.student;
    }
    setupController(controller, model) {
        super.setupController(controller, model);
        controller.set('student', this.student);
    }
}

app/controllers/test1.js

Javascript

import Ember from 'ember';
import EmberObject from '@ember/object';
import { cacheFor, destroy } from '@ember/object';
 
export default Ember.Controller.extend({
    actions: {
 
        del() {
            let temp = this.student.removeObserver('marks', this.student,
                'Changed');
            console.log('Observer removed!!')
        },
        Change() {
            this.student.set('marks', this.student.get('marks') + 10);
        },
 
    }
});

app/templates/test1.hbs

HTML

{{page-title "ArrayProxy"}}
<table>
    <h1>Student's Details:</h1>
    <div><b>Name:</b> {{this.student.name}}</div>
    <div><b>Gender:</b> {{this.student.gender}}</div>
    <div><b>Class:</b> {{this.student.class}}</div>
    <div><b>Mobile:</b> {{this.student.mobile}}</div>
    <div><b>Grade:</b> {{this.student.Grade}}</div>
    <div><b>Marks:</b> {{this.student.marks}}</div>
    <div><b>Branch:</b> {{this.student.Branch}}</div>
     
 
</table>
<br /><br/>
<input
    type="button"
    id="remove"
    value="Remove Observer"
    {{action 'del'}}
/><br /><br/>
<input
    type="button"
    id="Change"
    value="Change The Marks"
    {{action 'Change'}}
/>
{{outlet}}

Output:

removeObserver output1

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

ember generate route test2

app/routes/test2.js

Javascript

import Route from '@ember/routing/route';
import { computed } from '@ember/object';
import { tracked } from '@glimmer/tracking';
import Ember from 'ember';
import ArrayProxy from '@ember/object/proxy';
 
const Employee = ArrayProxy.extend({
 
    fullName: computed('firstName', 'lastName', function () {
        return this.get('firstName') + ' ' +
            this.get('lastName');
    }),
    change: Ember.observer('age', function () {
        console.log(`Age is changed`);
    }),
});
 
export default class DetailsRoute extends Route {
 
    value = 34;
    @tracked
    person = Employee.create({
        firstName: 'Rohil',
        lastName: 'Sahu',
        mobile: '928393839',
        age: 32,
        language: 'Hindi',
        country: 'India',
        gender: 'M',
        zipCode: '9384983',
        salary: 120000,
    });
 
    model() {
        return this.person
    }
    setupController(controller, model) {
        super.setupController(controller, model);
        controller.set('person', this.person);
        controller.set('value', this.value);
    }
}

app/controllers/test2.js

Javascript

import Ember from 'ember';
import EmberObject from '@ember/object';
 
 
export default Ember.Controller.extend({
 
    actions: {
 
        change(data) {
            this.person.set('age', data);
        },
 
        remove() {
            this.person.removeObserver('age', this.person, 'change');
            console.log('Observer Removed!!!')
        }
    }
});

app/templates/test2.hbs

HTML

{{page-title "ArrayProxy"}}
<table>
 
    <h1>Employee's Details: </h1>
    <div><b>Name:</b> {{this.person.fullName}}</div>
    <div><b>Gender:</b> {{this.person.gender}}</div>
    <div><b>Country:</b> {{this.person.country}}</div>
    <div><b>Salary:</b> {{this.person.salary}}</div>
    <div><b>Zip Code:</b> {{this.person.zipCode}}</div>
    <div><b>Language Speaks:</b>{{this.person.language}}</div>
    <div><b>Mobile No.:</b>{{this.person.mobile}}</div>
    <div><b>Age:</b> {{this.person.age}}</div>
</table>
 
 
<br />
{{input value=this.value}}
<br/>
<input
    type="button"
    id="Change"
    value="Change Age"
    {{action 'change'this.value}}
><br/><br/>
<input
    type="button"
    id="remove"
    value="Remove Observer"
    {{action 'remove'}}
>
{{outlet}}