AngularJS vs. Angular 2 Vs. Angular 4: Key Differences

What is Angular? 

Angular is an open-source, JavaScript framework written in TypeScript. Google maintains it and provides a standard structure for developers to work within it. Angular makes use of HTML syntax to define the components of your program clearly. It enables developers to build large applications in a maintainable manner. 

Read more: What is Angular?: Architecture, Features, and Advantages

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Types of Angular Versions

Before we dive into the differences, let’s first clarify each angular version with a description:

• AngularJS

  is an open-source, JavaScript-based, front-end web application framework for dynamic web app development. It utilizes HTML as a template language. By extending HTML attributes with directives and binding data to HTML with expressions, AngularJS creates an environment that is readable, extraordinarily expressive and quick to develop. 

• Angular 2

  is the blanket term used to refer to Angular 2, Angular 4 and all other versions that come after AngularJS. Both Angular 2 and 4 are open-source, TypeScript-based front-end web application platforms. 

• Angular 4

  is the latest version of Angular. Although Angular 2 was a complete rewrite of AngularJS, there are no major differences between Angular 2 and Angular 4. Angular 4 is only an improvement and is backward compatible with Angular 2. 

Components of Angular vs AngularJS

The main difference between a JavaScript-based framework and a TypeScript one can be seen in their components. Angular uses TypeScript and has components as its main building blocks. It is component-based, whereas AngularJS uses directives. 

Angular's operation employs a hierarchy of components, while AngularJS has directives that allow code reusability. So, The AngularJS framework provides reusable components for its users. AngularJS also uses controllers and scopes. Although Angular has standard directives, the two frameworks implement them differently. 

The Angular components play a significant role in creating user interfaces where every UI portion is defined as a component. In AngularJs, the same task is done using component directives. AngularJS component directive can be migrated to Angular with a few configurations. 

Use of Directives Between Angular vs AngularJS

Angular includes standard directives, and AngularJS contains a pack of them. So, both AngularJS and Angular use directives, but they use them differently. For instance, one can use the ng-model to create a two-way binding in AngularJS. The ng-bind directive is suitable for one-way binding. 

Contrastingly, Angular has only the ngModel. Using symbols, one can specify the type of binding: one-way binding as:" []," and two-way binding as:" [()]." "()" is for event binding, and "[]" is for property binding. 

Why Angular?

• It has a mobile support framework.
• The latest Angular version supports TypeScript and enables code optimization and modularity by employing the OOPS concept.
• It supports the changes for an increased hierarchical dependencies system. 
• A developer can use various features such as syntax for type checking, Dart, TypeScript, ES5, iterators, Angular CLI, ES6, and lambda operators.
• Angular opts for semantic versioning that has a major-minor-patch arrangement.
• Amongst its best benefits is its provision for the event of simplest routing.

Are you new to Angular? Check out the Angular tutorial here.

Why AngularJS?

• Its secure MVC (Model-View-Controller) data binding makes application performance dynamic.
• A developer can easily perform unit testing or change detection at any point. 
• It provides several helpful features for web developers, like declarative template language with HTML to allow them to make it more intuitive.
• The open-source framework allows well-structured front end development. It doesn't require any plugin or other platforms to work.
• The AngularJS application runs on Android and iOS phones and tablets.

Difference Between AngularJs and Angular Versions

Below is a comparison of AngularJS to Angular, because Angular includes both version 2 and version 4. We compare architecture, language, expression syntax, mobile support, and routing. 

1. Architecture

AngularJS

The architecture of AngularJS is based on the model-view-controller (MVC) design. The model is the central component that expresses the application's behavior and manages its data, logic, and rules. The view generates an output based on the information in the model. The controller accepts input, converts it into commands and sends the commands to the model and the view. 

Angular

Angular uses components and directives. Components are directives with a template.

Angular 2 

In Angular 2, controllers and $scope were replaced by components and directives. Components are directives with a template. They deal with a view of the application and logic on the page. There are two kinds of directives in Angular 2. These are structural directives that alter the layout of the DOM by removing and replacing its elements, and attributive directives that change the behavior or appearance of a DOM element.

In Angular 4, the structural derivatives ngIf and ngFor have been improved, and you can use if/else design syntax in your templates.   

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2. Language

AngularJS

AngularJS is written in JavaScript. 

Angular versions

Angular uses Microsoft’s TypeScript language, which is a superset of JavaScript. This has advantages like type declarations, and the benefits of ES6, like iterators and lambdas

Angular 4 is compatible with the most recent versions of TypeScript that have powerful type checking and object-oriented features. 

3. Expression Syntax

AngularJS

To bind an image/property or an event with AngularJS, you have to remember the right ng directive.

Angular versions

Angular focuses on “( )” for event binding and “[ ]” for property binding.

4. Mobile Support

AngularJS was not built with mobile support in mind, but Angular, Angular 2 and 4 feature mobile support.

5. Routing

AngularJS uses $routeprovider.when() to configure routing while Angular uses @RouteConfig{(…)}. 

6. Performance 

AngularJS was originally developed for designers, not developers. Although there were a few evolutionary improvements in its design, they were not enough to fulfill developer requirements. The later versions, Angular 2 and Angular 4, have been upgraded to provide an overall improvement in performance, especially in speed and dependency injection. 

• Speed

By providing features like 2-way binding, AngularJS reduced the development effort and time. However, by creating more processing on the client-side, page load was taking considerable time. Angular2 provides a better structure to more easily create and maintain big applications and a better change detection mechanism. Angular 4 is the fastest version yet.

• Dependency Injection

Angular implements unidirectional tree-based change detection and uses the Hierarchical Dependency Injection system. This significantly boosts performance for the framework.

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Have a look at the table below for a concise report on the differences between Angular and AngularJS

Advantages and Disadvantages of AngularJs and Angular Versions

Because they are Google products, all Angular versions are trustworthy and enjoy great support from Google engineers and the large community of Angular users and developers. However, each angular version has its own advantages and disadvantages. 

1. AngularJS

Advantages

• It is unit testing ready.
• It has great MVC data binding that makes app development fast.
• Using HTML as a declarative language makes it very intuitive.
• It is a comprehensive solution for rapid front-end development since it does not need any other frameworks or plugins.
• AngularJS apps can run on every significant program and advanced cells including iOS and Android-based phones and tablets.

Disadvantages

• It is big and complicated due to the multiple ways of doing the same thing.
• Implementations scale poorly.
• If a user of an AngularJS application disables JavaScript, nothing but the basic page is visible.
• There’s a lagging UI if there are more than 200 watchers.

2. Angular 2

Advantages

• TypeScript allows code optimization using the OOPS concept.
• It is mobile-oriented.
• It has improved dependency injection and modularity.
• It provides more choice for languages such as Dart, TypeScript, ES5, and ES6 for writing codes.
• It offers simpler routing.

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Disadvantages

• It is more complicated to set up compared to AngularJS.
• It’s inefficient if you only need to create simple, small web apps. 

3. Angular 4

Advantages

• It enables a fast development process.
• It’s ideal for single-page web applications with an extended interface.
• Full TypeScript support helps in building bulky applications.
• Tests are easy to write.
• An improved View Engine generates less code in AOT mode.
• It has a modularized animation package.

Disadvantages

• It’s slow when displaying enormous amounts of data.

Also Read: How to Become an Angular Developer in 2022

Frequently Asked Questions

1. Is Angular better than AngularJS?

Angular allows improved algorithms for data binding. It has a component-based architecture. In contrast, Angular.JS has the two-way binding property that enables faster and easier binding without any involvement of professionals. Angular project elements are quite self-sufficient and independent, while AngularJS is highly recommended for swift coding and prototyping. So, an individual's requirements make Angular or AngularJS a better option for them. 

2. Why use AngularJS?

AngularJS features make application development easy and quick, promising very intuitive results. AngularJS components and directives allow the much sought-after functionality to HTML. They can be operated for creating custom-built HTML tags that facilitate fresh and tailored widgets. The ability to detect a change and perform unit testing anytime makes AngularJS a preferred framework. 

3. What is the use of AngularJS?

AngularJS is a popular web framework developers use for building weather, eCommerce, video-streaming, travel, user-review, social, and user-generated applications. The Guardian, Upwork, PayPal, Freelancer, Netflix, LinkedIn, and other popular apps are built using AngularJS.  

Conclusion

Obviously, AngularJS is still useful or else everyone would have migrated to Angular 2 or 4 by now. Each version of Angular has significant benefits, but there is much to gain in being up-to-date with the latest version. Angular is decidedly faster than AngularJS, has a mobile-driven approach,  executes better with components, and enables smoother migration from earlier versions. If you are comfortable with one version of Angular, switching to another should be easy for you—and well worth the effort.