Ember.js ObjectProxy Class
Last Updated :
29 Jan, 2023
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.
ObjectProxy Class: The ObjectProxy is a proxy object class in Ember.js. All properties not defined by the proxy itself are forwarded to a proxied content object via ObjectProxy.
Methods: The following is the list of methods for this class:
- addObserver: This method is used to register an observer for a property.
- cacheFor: This method is used to get the cached value for an already computed property if it exists.
- 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.
- get: This method is used to retrieve the value of a property from the object.
- getProperties: This method is used to get the value of multiple properties at once.
- incrementProperty: This method is used to set the value of the property to the current value plus some amount.
- init: This method is called when objects are instantiated.
- notifyPropertyChange: This method alerts the observer system that a property change has taken place.
- removeObserver: This method removes any observers you have registered earlier for this object.
- set: This method is used to set the key and value to the object.
- setProperties: This method sets a number of properties at once.
- 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.
- willDestroy: This method tears down the object.
Properties: The following is the list of the properties of this class:
- concatenatedProperties: This property specifies the characteristics from the superclass that will be concatenated
- content: This property is used to forward the object property.
- isDestroyed: This property is the destroy complete flag.
- isDestroying: This property is the destroy scheduled flag.
- 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 get function.
Type the following code to generate the route for this example:
ember generate route students
app/routes/students.js
Javascript
import Route from '@ember/routing/route' ;
import EmberObject from '@ember/object' ;
export default class StudentsRoute extends Route {
students = [
EmberObject.create({ name: 'Rahul' ,
Class: 11, marks: 75 }),
EmberObject.create({ name: 'Sam' ,
Class: 12, marks: 59 }),
EmberObject.create({ name: 'David' ,
Class: 11, marks: 67 }),
EmberObject.create({ name: 'Druv' ,
Class: 12, marks: 44 }),
EmberObject.create({ name: 'Mahan' ,
Class: 12, marks: 87 }),
EmberObject.create({ name: 'Ram' ,
Class: 11, marks: 71 }),
EmberObject.create({ name: 'Dadu' ,
Class: 12, marks: 58 })
];
model() {
return this .students;
}
setupController(controller, model) {
super .setupController(controller, model);
controller.set( 'students' , this .students);
}
}
|
app/controllers/students.js
Javascript
import Ember from "ember" ;
import { isAny, isEvery } from "@ember/array" ;
export default Ember.Controller.extend({
actions: {
increase(data) {
this .students.forEach((item) =>
item.incrementProperty( 'marks' ,
JSON.parse(data)));
},
decrease(data) {
this .students.forEach((item) =>
item.decrementProperty( 'marks' ,
JSON.parse(data)));
},
remove(item) {
this .students.set( '[]' , this .students.without
( this .students.findBy( 'name' , item)));
},
show_first() {
let ans = this .students.get( 'firstObject' );
alert(ans.name)
},
show_last() {
let ans = this .students.get( 'lastObject' );
alert(ans.name)
},
},
});
|
app/template/students.hbs
HTML
{{page-title "get"}}
< h3 >Students List: </ h3 >
< table >
< tr >
< th >Name</ th >
< th >Class</ th >
< th >Marks</ th >
</ tr >
{{#each @model as |detail|}}
< tr >
< td >{{detail.name}}</ td >
< td >{{detail.Class}}</ td >
< td >{{detail.marks}}</ td >
</ tr >
{{/each}}
</ table >
< br />
< div >
< label >Enter value: </ label >
{{input value=this.item}}
</ div >
< input
type = "button"
id = "increase-marks"
value = "Increase All marks by Value"
{{action "increase" this.item}}
/>
< br />< br />
< div >
< label >Enter value: </ label >
{{input value=this.item2}}
</ div >
< input
type = "button"
id = "decrease-marks"
value = "decrease All marks by Value"
{{action "decrease" this.item2}}
/>
< br />< br />
< div >
< label >Enter Name: </ label >
{{input value=this.item3}}
</ div >
< input
type = "button"
id = "remove-student"
value = "Remove Student"
{{action "remove" this.item3}}
/>
< br />< br />
< input
type = "button"
id = "first-student"
value = "Show First Student in list"
{{action "show_first"}}
/>
< br />< br />
< input
type = "button"
id = "last-student"
value = "Show Last Student in list"
{{action "show_last"}}
/>
{{outlet}}
|
Output:
Example 2: In this example, we are going to take a look at the incrementProperty and decrementProperty methods.
Type the following code to generate the route for this example:
ember generate route foods
app/routes/foods.js
Javascript
import Route from '@ember/routing/route' ;
import EmberObject from '@ember/object' ;
export default class FoodsRoute extends Route {
temp;
model() {
return 'Increment Property' ;
}
setupController(controller, model) {
super .setupController(controller, model);
controller.set( 'temp' , this .temp);
controller.set( 'temp2' , this .temp2);
}
}
|
app/controllers/foods.js
Javascript
import Ember from 'ember' ;
import EmberObject from '@ember/object' ;
const Food = EmberObject.extend({
toStringExtension() {
return this .get( 'food' );
}
});
export default Ember.Controller.extend({
value: 0,
food: [
Food.create({
food: 'apple' ,
isFruit: true ,
quant: '1' ,
}),
Food.create({
food: 'Potato' ,
isFruit: false ,
quant: '2' ,
}),
Food.create({
food: 'Banana' ,
isFruit: true ,
quant: '1' ,
}),
Food.create({
food: 'Burgur' ,
isFruit: false ,
quant: '2' ,
}),
Food.create({
food: 'Orange' ,
isFruit: true ,
quant: '1' ,
}),
Food.create({
food: 'sandwitch' ,
isFruit: false ,
quant: '2' ,
}),
Food.create({
food: 'bean' ,
isFruit: false ,
quant: '2' ,
}),
],
actions: {
older() {
this .incrementProperty( 'value' );
},
younger() {
this .decrementProperty( 'value' );
},
addItem(data, data1, data2) {
let temp = Food.create({
food: data,
isFruit: data1,
quant: data2
});
alert(temp.toString() + ' Created' );
this .food.addObject(temp);
}
}
});
|
app/template/foods.hbs
HTML
{{page-title "incrementProperty"}}
< h3 >List of Item in Buckets</ h3 >
< table >
< tr >
< th >Food Name </ th >
< th >Bucket </ th >
< th >Fruit </ th >
</ tr >
{{#each this.food as |f|}}
< tr >
< td >{{f.food}}</ td >
< td >{{f.quant}}</ td >
< td >{{f.isFruit}}</ td >
</ tr >
{{/each}}
</ table >
< br />< br />
< div >
< label >Enter Item Name: </ label >
{{input value=this.temp2}}
</ div >
< br />
< div >
< label >Enter Quantity in Kg: </ label >
{{input value=this.value}}
</ div >
< input
type = "button"
id = "increase"
value = "+"
{{action "older"}} />
< input
type = "button"
id = "decrease"
value = "-"
{{action "younger"}} />
< br />
< br />
< div >
< label >Item is fruit of not : </ label >
{{input value=this.temp}}
</ div >
< br />< br />
< input
type = "button"
id = "all-Fruits"
value = "Add item"
{{action "addItem" this.temp2 this.value this.temp}}
/>
{{outlet}}
|
Output:
Reference: https://api.emberjs.com/ember/release/classes/ObjectProxy
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