Angular 4 the extended version of Angular 1 and Angular 2.0. Angular 4.0.0 is smaller and faster and has so many improved features. It includes major improvements and functionality.
Some prominent features of Angular 4 are below:
Compatibility: Application written using Angular 2 will be compatible with Angular 4 as well.
TypeScript: The version of TypeScript is upgraded from 1.8 to 2.1. This will improve the speed of ngc and one will get better type checking throughout one’s application.
In-Built Compiler: Angular 4 comes with the inbuilt compiler to report the template errors right in the IDE. Google emphasizes improvements in tooling as well as reduced code generation.
Reduction of Code: Changes to AOT generated code such that one will find reduction in the size of the generated code for the components by around 60% in most of the cases.
Animation Package: segregated animation package from @angular/core as a separate and dedication package. Therefore, if one don’t use animations, this extra code will not end up in your production bundles.
Improved *ngIf and *ngFor: if/else style syntax has been introduced where one can assign local variables such as when unrolling an observable.
Flat ES Modules: Modules are shipped as flattened version that helps in tree-shaking and reduce the size of generated bundles. It also speeds up the building process and loading in the browser in certain scenarios.