Angular 9 new features

In Angular 9 all applications uses Ivy compiler and runtime by default and hence Angular 9 has following improvements.

Angular uses tree-shaking to generate less code for component and hence we can see the dramatic difference in sizes of small and big apps bundle.

The TestBed is revamped in Ivy to make it more efficient. Previously TestBed recompiles all components between the running of each test even if there is no change. Now in Ivy the TestBed recompiles a component only if a component has been manually overridden.

Ivy provides more tools to debug the applications. Now Angular has a ng object for debugging .

Now better control of style binding to merge in predictable way.

Now Angular compiler can check more of the types of our applications and it can apply more strict rules.

Now error message are more easier to read to understand the root cause of error.

Angular has improved the build times using Ivy. Now our projects can compile faster than before.

In Angular 9,  the build-time i18n substitutions has been moved later in the build process. By this change, build process in i18n has been 10 times faster.