AngularJS (also known as Angular 1.x) and Angular 2+ (which includes Angular 2, 4, 5, and later versions) are fundamentally different frameworks. While AngularJS is based on JavaScript and follows an MVC architecture, Angular 2+ is built using TypeScript and follows a component-based architecture. Below is a detailed comparison of AngularJS vs Angular 2+.
1. Architecture
Feature
AngularJS (1.x)
Angular 2+
Pattern
MVC (Model-View-Controller)
Component-based architecture
Structure
Controllers, Directives, Services
Components, Services, Modules
Complexity
Complex two-way binding
Simplified with one-way data flow
Explanation
AngularJS uses controllers and scope to manage data.
Angular 2+ replaces controllers with components, making applications more modular and reusable.
2. Language
Feature
AngularJS (1.x)
Angular 2+
Primary Language
JavaScript
TypeScript (Super-set of JavaScript)
Support for ES6+
Limited
Fully supported
Strict Typing
No
Yes
Explanation
AngularJS is written in JavaScript, which is dynamically typed.
Angular 2+ is built on TypeScript, which is statically typed, making development easier and error-free.
3. Performance & Speed
Feature
AngularJS (1.x)
Angular 2+
Performance
Slower (due to two-way binding)
Faster (with improved change detection)
Rendering
Uses dirty checking
Uses zone.js and improved change detection
Mobile Support
No
Yes
Explanation
Angular 2+ improves performance using a virtual DOM and a better change detection strategy, making it much faster than AngularJS.
AngularJS checks for changes in every digest cycle, which slows performance.
4. Data Binding
Feature
AngularJS (1.x)
Angular 2+
Binding Type
Two-way data binding
One-way & Two-way data binding
Change Detection
Uses digest cycle
Uses Zone.js & Observables
Explanation
AngularJS updates both the model and view automatically, but this causes performance issues.
Angular 2+ uses one-way binding by default, reducing unnecessary DOM updates.
5. Directives & Components
Feature
AngularJS (1.x)
Angular 2+
Directives
Many built-in directives
Simplified directives
Components
Not available
Core concept
Explanation
AngularJS uses directives like ng-controller, ng-model, and ng-repeat.
Angular 2+ uses components instead of controllers, making code more structured and reusable.
6. Dependency Injection (DI)
Feature
AngularJS (1.x)
Angular 2+
Dependency Injection
Limited support
Fully hierarchical DI
Service Injection
Uses $injector
Uses @Injectable decorator
Explanation
Angular 2+ has a powerful, hierarchical DI system, making dependencies more efficient.
AngularJS requires manually injecting dependencies, which can be complex.
7. Routing
Feature
AngularJS (1.x)
Angular 2+
Routing Module
$routeProvider
@angular/router
Lazy Loading
No
Yes
Explanation
Angular 2+ uses a more advanced router with lazy loading, improving performance.
AngularJS uses $routeProvider, which does not support lazy loading.
8. Mobile Support
Feature
AngularJS (1.x)
Angular 2+
Mobile-Friendly
No
Yes
Responsive Design
Needs extra frameworks
Built-in support
Explanation
Angular 2+ is designed for mobile-first applications with built-in optimizations.
AngularJS lacks native mobile support.
9. Build & Tooling
Feature
AngularJS (1.x)
Angular 2+
Build Tools
Manual (Gulp, Grunt)
Angular CLI
Code Bundling
No
Yes
Compilation
Interpreted at runtime
AOT (Ahead-of-Time) Compilation
Explanation
Angular 2+ uses the Angular CLI for project setup, making development faster.
Ahead-of-Time (AOT) compilation in Angular 2+ improves performance.
10. Testing
Feature
AngularJS (1.x)
Angular 2+
Testing Framework
Jasmine, Karma
Jasmine, Karma, Protractor
Unit Testing
Difficult due to scope and controllers
Easier due to modular components
Explanation
Angular 2+ is easier to test due to its modular structure.
AngularJS controllers and $scope make testing more complex.
11. Backward Compatibility
Feature
AngularJS (1.x)
Angular 2+
Backward Compatibility
Not compatible with Angular 2+
Supports Angular 4, 5, and later
Explanation
AngularJS applications cannot be directly upgraded to Angular 2+.
