Angular libraries are NgModules, such as FormsModule, HttpClientModule, and RouterModule. Many third-party libraries are available as NgModules such as Material Design, Ionic, and AngularFire2.
NgModules consolidate components, directives, and pipes into cohesive blocks of functionality, each focused on a feature area, application business domain, workflow, or common collection of utilities.
- declarations: The components, directives, and pipes that belong to this NgModule.
- exports: The subset of declarations that should be visible and usable in the component templates of other NgModules.
- imports: Other modules whose exported classes are needed by component templates declared in this NgModule.
- providers: Creators of services that this NgModule contributes to the global collection of services; they become accessible in all parts of the app. (You can also specify providers at the component level, which is often preferred.)
- Entry Components: An entry component is any component that Angular loads imperatively, (which means you’re not referencing it in the template), by type. You specify an entry component by bootstrapping it in an NgModule, or including it in a routing definition.
