Difference between AngularJS Expression and Angular Expression - Coding

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= 
"https://ajax.googleapis.com/ajax/libs/angularjs/1.8.2/angular.min.js"> 
    </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.

Reffered: https://www.geeksforgeeks.org

AngularJS

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Category:	Coding
Sub Category:	Tutorial
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