Angular is a platform and framework which makes easy to develop applications with the web in HTML and typescript. To solve development challenges faced by developers Angular combines declarative templates, dependency injection, an end to end tooling, and integrated best practices. Angular empowers developers to build client applications that live on the mobile, web, or the desktop. Till now Google has released the following versions of Angular which are popular for client-side JavaScript.

• AngularJS is also referred to as “Angular.js” or Angular 1.x
• It is a JavaScript-based framework which is open-source and used in front-end web application development.
• It is mainly maintained by Google and by a community of individuals and corporations to address many of the problems faced in developing single-page applications.
• It mainly built to simplify both the development and the testing of applications by providing a framework for client-side model–view–controller (MVC) and model–view–ViewModel (MVVM) architectures, along with components commonly used in rich Internet applications.
• The current stable version is 1.6.10 (v1.7 is near to release)
• Angular development code is written in JavaScript

• Angular 2 is a rewritten by the same team that built AngularJS.
• The whole concept is written entirely in TypeScript.
• Angular 1.x was not built with the purpose to support mobile, where Angular 2 is mobile oriented.
• It was released in September 2016.
• To write Angular 2 code, it provides a wide range of choice for languages you can use any of the languages from ES5, ES6, TypeScript or Dart.

Angular 3 was skipped.

The reason behind this is that version mismatch between @angular/core, @angular/compiler and @angular/router libraries. The core and router for Angular 2 version are like following:

Now the problem is with @angular/router, which is already in a 3.X version. These problems occur because of some active and huge developments on the router section, like route-preload.

Now, the launch of Angular as version 3, with its path in version 4 will create confusion.

To avoid this confusion, they decided to skip version 3 and release it with version 4.0.0 so that every major unit was on the right track.

For most applications, this release is backward compatible with 2.x.x.Angular 2 and was released in March 2017 and there is no major change in Angular 4 from Angular 2. Angular 4 is not the complete rewritten form of Angular 2.

The Angular team has laid emphasis on making angular apps faster and compact.

• Under the hood changes: By the new changes, the size of the generated code for your components is reduced by around 60% in most cases.
• Faster Compilation
• Better Bug fixes Alert.
• TypeScript 2.1 and 2.2 compatibility: Finally We can use typescript 2.1 or earlier only upto typescript 1.8 was supported.
• *ngIf/else: Now the feature to use else clause is also available.
• For email validation in angular 4, there is No need to write a pattern.

Angular 5 was launched in Nov 2017. According to its speed and size, It was way faster and of smaller size than that of Angular 4. Here’s the failure of some of the biggest changes in v5. For the full list, please see the changelog. Following features were introduced in Angular 5.

• HTTPClient API − HTTPClient API was introduced to simplify the HTTP library for Angular applications that rest on the XMLHttpRequest interface exposed by browsers. It is much secure, faster, efficient than HTTP library and provides additional features like testability, typed request and response objects
• Multiple export aliases − To ease the migration process a component can be exported with the help of multiple aliases.
• Internationalized Pipes for Number, Date, and Currency −Earlier Angular versions was dependant on the browsers to get the number, date and currency format. This resulted in inconsistency for users but in v5 pipes were updated for better standardization.
• Lambda support − lambda expressions with proper names can be used in place of functions.
• Build Optimizer - Build Optimizer is also introduced. It contains Angular optimizations applicable to JavaScript code as a TypeScript transform pipeline which optimizes the build size and improves the application speed. Angular CLI uses Build Optimizer automatically.
• Improved Compiler − Angular 5 onwards, the compiler supports incremental compilation leading to faster compilation. The compiler uses TypeScript transforms, a new feature of TypeScript 2.3 available onwards.

Angular 6.0.0 was launched on May 4th, 2018. Angular 6 was released with Angular CLI 6 and Material 6.Here’s a breakdown of some of the biggest changes in v6. For the full list, please see the changelog

• Updated Angular CLI (Command Line interface) − New commands added, like ng-update to migrate from the previous version to current version. ng-add to quickly add application features to make application progressive web apps.
• Updated CDK, Component Development Kit − Supports creating custom UI elements without the need of the angular material library. Supports responsive web design layouts. Supports overlay packages to create pop-ups.
• Updated Angular Material − New Tree component added, mat-tree, a styled version, and cdk-tree, an unstyled version, to represent a hierarchical structure like a tree.
• Usage of RxJS, a reactive JS library
• Angular Element -They are angular Components packaged as custom elements which then used for defining new HTML elements.
• Multiple Validators −Validating user input for accuracy and completeness multiple validators are applicable on a form builder.
• Tree Shaking on Services − Now tree shaking can be applied on services to remove the dead code, which means removes the code from the final bundle if that code not referenced in an application.

Angular 7 was released in Oct 18, 2018. Let's see the new features added to Angular 7 −

Here’s a breakdown of some of the biggest changes in v6. For the full list, please see the changelog

• How to upgrade to Angular 7
• Angular 7 CLI Prompts
• Application Performance
• Documentation Updates
• Dependency Updates
• Drag and Drop
• Virtual Scrolling
• Improved Accessibility of Selects
• Partner Launches
• Angular Elements
• Angular Do-Bootstrap

The following table contains current target release dates for the next two major versions of Angular: