
Angular 9 provides type safe changes in TestBed API changes by replacing the old get function with the new inject method. Because TestBed.get method is not type-safe. The usage would be as below,

```javascript
TestBed.get(ChangeDetectorRef); // returns any. It is deprecated now.

TestBed.inject(ChangeDetectorRef); // returns ChangeDetectorRef
```

What are type safe TestBed API changes in Angular9?

Angular is a TypeScript-based open-source front-end platform that makes it easy to build applications with in web/mobile/desktop.

What is Angular Framework?

Modules are logical boundaries in your application and the application is divided into separate modules to separate the functionality of your application.

What is a Angular module?

What are the steps to use animation module?

Learn about ngcc, the Angular Compatibility Compiler, and how it allows you to use existing libraries in Angular Ivy projects.

What is ngcc in Angular Ivy and why is it important?

Polyfills are a tool for Angular developers, allowing them to use new features of JavaScript without worrying about compatibility with older browsers.

How to use polyfills in Angular application?

How do you manually register locale data?

The ngIf and hidden properties in Angular control element visibility in different ways.