Developed and maintained by Google and a community of developers, AngularJS (now evolved to Angular) is one of the best and most widely used front-end web application platform. The journey of the platform started from AngularJS being the first release moving on to Angular 2 and now Angular 4.
Initially, the platform was based on JavaScript in the first release but moved on to TypeScript in its later versions, as it offered a few more crucial features. In other words, Angular is a complete rewrite of AngularJS, created by the same backend team.

Since it is an industry leader, Google constantly works to evolve and set benchmarks of progress in any domain. Angular is also one of them. After the release of AngularJS, Google’s team immediately started analyzing and working on making the framework better.

As a part of those steps of progress, in March 2017, the Angular team launched another version of the framework, Angular 4 or Angular v4 which was a step ahead of the previous one, Angular 2. The number 3 was skipped to avoid confusion with the router package version which was already release as v3.

Now that we have a brief idea about the platform, we can move on to see what’s new in Angular 4 from its previous version.

What’s new in Angular 4?

Although there is quite a lot that’s different in Angular 4, given below are 5 important features of Angular 4 that are an improvement over Angular 2.

1.Angular Universal:  


Angular Universal is an incredible library that makes creating Universal apps a lot easier. It was initially introduced in Angular 2 as a solution to render to a virtual DOM via server requests.

However, the library was maintained as a separate entity in Angular 2. In Angular 4 however, Angular Universal is now a part of the core Angular Module which makes it easy to import the functions from the library.

2. Animation Package:


Animations have been a big part of Angular. However, in Angular 2, the animation functions were provided in the core Angular Module. This meant that even if you did not use any of the animations, the code for them was always in your applications.

In Angular 4, the animation function gets an independent package in order to discard all the useless code from the bundle that was shipped to the users. Animation functions now will have to be imported from their own package for use.

3. Template Changes

In the templates, there are primarily three significant improvements in Angular 4 from Angular 2 that we need to keep in mind. Firstly, the “template” tag is now deprecated to be replaced with a new template tage: “ng-template”. This was to avoid confusion with the “template” HTML tag.

Secondly, in Angular 4, you can now use the “else” syntax along with “ngIf” in your templates. Lastly, the addition of the “as” keyword in the template syntax will now allow you to store a result in a variable of the template.

4. Router

Angular 4 introduces a new interface to represent URL parameters. This is known as ParaMap. They offer a choice to the developer to get a single value or all the values of a URL query parameter, since it can have multiple.

Although the change is not too hard for Angular developers , they will now have to use ParaMap or queryParaMap instead of using Params and queryParams in Angular 2.

5. Speed and Performance


A very expected change in Angular 4 is the increase in speed and performance of the applications developed by it. This is primarily due to the improvement of the View Engine for the Ahead of Time Compilation function.

The only downside to Ahead of Time compilation is that the generated JavaScript is larger than the uncompiled HTML templates. The Angular team worked to improve the View Engine that produces less code for AoT compilations and reduces the size of the application significantly without compromising on the performance. This also increases the speed of the application really well.

So these were a few of the major changes in Angular 4 that are a huge improvement over Angular 2. With the new release, the Angular team has brought out some really amazing features for the framework and as per the previous records, we know that these will only improve in future versions. Angular 4 continues to uphold the incredible reputation of the platform.