Difference between AngularJS Expression and Angular Expression
AngularJS is a JavaScript-based framework that can be used by adding it to an HTML page using a <script> tag. AngularJS helps in extending the HTML attributes with the help of directives and binding of data to the HTML with expressions. Angular on the other hand is a client-side TypeScript-based, front-end web framework by Google.
Angular is a great, reusable UI (User Interface) library for developers that help in building attractive, and steady web pages and web application.
An Expression in Angular or Angular JS is a code snippet that can be simple or complex JavaScript-like code, like, the variable references, function calls, operators, and filters, etc, written within double curly braces {{ }} in order to evaluate & display dynamic values or perform calculations in the template.
In this article, we will learn about Angular Expression & Angular JS Expression, their implementations & the difference between them.
AngularJS Expression
AngularJS, the predecessor of Angular, introduced the concept of expressions as a way to bind dynamic data to HTML templates. AngularJS Expressions are written within double curly braces {{ }} and are evaluated by the framework to generate values displayed in the UI. These expressions are based on JavaScript and can include variables, function calls, operators, and literals.
Syntax:
In the below syntax, the msg variable is defined in the AngularJS controller and its value will be displayed in the <p> element.
<p>
{{ mymsg }}
</p>
Example: Below example demonstrates the usage of expressions in the Angular JS application.
HTML
<!DOCTYPE html> <html ng-app="myApp"> <head> <title> Angular JS Expression </title> <script src= </script> </head> <body> <div ng-controller="MyCtrl"> <h1 style="color: green"> GeeksforGeeks </h1> <h2>AngularJS Expressions </h2> <p>{{ mymsg }}</p> </div> <script> angular.module('myApp', []) .controller('MyCtrl', function ($scope) { $scope.mymsg = 'Welcome to GeeksforGeeks!'; }); </script> </body> </html> |
Output:
Angular Expression
Angular takes a different approach to handle dynamic data by replacing expressions with a more powerful mechanism called Angular templates. Angular templates provide a declarative approach to data binding and are designed to offer enhanced flexibility and efficiency.
Syntax:
In the below syntax, the msg property is bound to the <p> element and its value will be displayed.
// app.component.html
<p>{{ mymsg }}</p>
// app.component.ts
export class AppComponent {
mymsg = 'Hello, Geek!';
}
Example: Below example demonstrates the usage of Expressions in the Angular application.
- newcomponent.component.ts
Javascript
import { Component } from '@angular/core'; @Component({ selector: 'app-welcome', templateUrl: './welcome.component.html', styleUrls: ['./welcome.component.css'] }) export class WelcomeComponent { mymsg: string = 'Welcome to GeeksforGeeks!'; } |
- newcomponent.component.html
HTML
<div> <h1 style="color: green"> GeeksforGeeks </h1> <h2>AngularJS Expressions </h2> <p>{{ mymsg }}</p> </div> |
- app.component.html
HTML
<div> <app-new-component></app-new-component> </div> |
Output:
Difference between AngularJS Expression and Angular Expression:
AngularJS Expression |
Angular Expression |
|---|---|
|
It is based on JavaScript language. |
It is based on the TypeScript language. |
|
The expressions are directly used within HTML templates. |
The expressions are used within Angular templates. |
|
The expressions are evaluated within the controller scope. |
The expressions are evaluated within the component context. |
|
AngularJS expressions have limited safety restrictions, as it permits potentially harmful operations. |
Angular Expressions, on the other side, provide safety restrictions for preventing harmful operations. |
|
The Expressions in Angular JS are less efficient in large-scale applications due to the digest cycle. |
The expressions in Angular are highly efficient in the detection mechanism for better performance in large-scale applications. |
