NgModule vs Component

Question

So I'm learning angular2 now and reading ngbook2 about the modules. Modules contain components, but also can import different modules with their public components.

And the question is: What is the scope of the module component (in this meaning scope as parts of an application, not the reach of variables inside). Is module the whole application or just some part like header, containing its components?

What is the typicaly used convention?

Answer 1

A common way is to see a module as a distinct feature implementation, that can consist of zero or more services, components, directives, and pipes and import modules that are used to implement that feature.

A module can define what of its content it exports to be made available for importers.

An application can consist of one or more modules with the root module importing zero or more modules where each imported module can import zero or more modules.

Modules can also be used to - split an app into parts that can be lazy loaded - reused in different applications - to create a naming scope for selectors.

A component is a reusable visual building block for the user interface that is rendered as HTML with event handlers to react on user actions and model data changes.

Answer 2

In one whole application, there can be one main Module. But your application can be divided into multiple modules and can be injected into the Main Module. Let's say you have a big application library which contains movies, trailer, songs etc. You gave the main app Module name 'MyApp'. but further you divided your app into multiple components say.

• MovieComponent
• SongComponent (further divided into AudioComponent and VideoComponent)
• TrailerComponent

All these Component developed and tested individually and integrated to our MyAppModule.

In case anything happens in our Trailer part we can discard/test our TrailerComponent.

So It is easy to maintain a large Applications.

I hope this will help you to understand. any suggestions most welcomed