Angular2

NgModule Overview

by @laco0416

 

about me

 

ng-sake

 

http://ng-sake.connpass.com/

 

NgModule

 
  • Mark application entry point
  • Configure platform

Module declaration

import {NgModule, ApplicationRef} from '@angular/core';
import {CommonModule} from '@angular/common';
import {FormsModule} from '@angular/forms';
import {MaterialModule} from '@angular2-material/module';
import {AppComponent} from './app.component';

@NgModule({
  declarations: [AppComponent],
  imports: [BrowserModule, CommonModule, FormsModule, MaterialModule],
  entryComponents: [AppComponent]
})
class AppModule {
  constructor(appRef: ApplicationRef) {
    appRef.bootstrap(AppComponent);
  }
}

bootstrapping

 
import {AppModule} from './app.module';
import {platformBrowserDynamic} from '@angular/browser-platform-dynamic';
platformBrowserDynamic().bootstrapModule(AppModule);
class NgModule {
  declarations: Array<ComponentType | DirectiveType | PipeType>;
  imports: Array<ModuleType | ModuleWithProviders>;
  exports: Array<ComponentType | DirectiveType | PipeType | ModuleType>;
  providers: Array<Providers | Array<any> >;
  entryComponents: Array<ComponentType>;
  schemas: Array<any>;
}

@NgModule

NgModule.declarations

  • List of your directives/pipes
  • Can be used anywhere
    • Loaded as platform stuff

NgModule.declarations

@NgModule({
     declarations: [
        AppComponent,
        MyComponent,
        MyDirective,
        MyPipe,
        ...SOME_LIBRALIES_DIRECTIVES
    ],
})

NgModule.providers

 
  • List of your providers
  • Can be injected anywhere
 

Module providers

@NgModule({
    providers: [
        MyService,
        SomeLibraryService,
    ],
})

NgModule.imports

 
  • Load other modules
  • Official modules
    • BrowserModule
    • HttpModule
    • RouterModule
    • FormsModule
    • MaterialModule
 

NgModule.exports

 
  • Module as a Library
  • Expose module's things 
 

Module exporting

@NgModule({
    declarations: [AwesomeComponent, AwesomePipe]
    exports: [AwesomeComponent, AwesomePipe],
    providers: [AwesomeService]
})
export class AwesomeModule {
}

NgModule.entryComponents

 
  • Initial components to compile
  • Use cases
    • AppComponent
    • Lazy Loading
 

Migration

 
Legacy New
bootstrap(.., [MyService]) NgModule.providers
Component.pipes NgModule.declarations
Component.directives NgModule.declarations
Component.providers NgModule.providers

RC.4

 
@Component({
    directives: [ MyComponent ],
    pipes: [ MyPipe ],
    providers: [ MyService ],
})
class AppComponent {
}

bootstrap(AppComponent, [
    HTTP_PROVIDERS
])

Legacy bootstrapping
with Modules

import {bootstrap} from '@angular/browser-platform-dynamic';
import {AppComponent} from './app.component';
import {FormsModule} from '@angular/forms';

bootstrap(AppComponent, {imports: [FormsModule]});

for migration

Why NgModule?

 
  • Component.directives/pipes
  • Providers inheritance
  • Library architecture
  • Easy to use
  • Easy to migrate from angular.module()
 
angular.module('app', ['ui.router'])
    .service('myService', MyService)
    .component('myComponent', {...})
    .config(() => {...});
@NgModule({
    imports: [RouterModule],
    delcarations: [MyComponent],
    providers: [MyService]
})
class AppModule {
    constructor() {
        ...
    }
}

Angular modules

 

Conclusion

 
  • Use NgModule.providers
    • Remove Component.providers
  • Use NgModule.declarations
    • Remove Component.directives/pipes
  • Keep single scope
  • Use modules
    • Http, Forms, Router, ...
  • Make modules
    • Module as a Library 
 

Docs

 

Thanks!

Angular2 NgModule Overview

By Suguru Inatomi

Angular2 NgModule Overview

Understanding @NgModule

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