CommonModule vs BrowserModule in angular

What you have to understand is, with Angular, you create modular application and there are two types of modules. One is root module and another is feature module.

• Root module imports the BrowserModule (if you are rendering in browser). This has the same stuffs as CommonModule but also stuffs that are used for rendering.
• Now if you are creating a feature module, since you already have BrowserModule imported in your root module, it does not make sense and it’s an overhead to import the Browser module in your feature module. Also, importing CommonModule  frees feature modules for use on any target platform (e.g. native mobile platform), not just browsers.
  That’s why you import CommonModule in your feature modules and BrowserModule in your root module.