bootstrap function

Future<ComponentRef> bootstrap (Type appComponentType, [ List customProviders ])

Bootstrapping for Angular applications.

You instantiate an Angular application by explicitly specifying a component to use as the root component for your application via the bootstrap method.

An application is bootstrapped inside an existing browser DOM, typically index.html. Unlike Angular 1, Angular 2 does not compile/process providers in index.html. This is mainly for security reasons, as well as architectural changes in Angular 2. This means that index.html can safely be processed using server-side technologies such as providers. Bindings can thus use double-curly syntax, {{...}}, without collision with Angular 2 {{...}} template syntax.

When an app developer invokes bootstrap with a root component as its argument, Angular performs the following tasks:

  1. It uses the component's selector property to locate the DOM element which needs to be upgraded into the angular component.
  2. It creates a new child injector (from the platform injector). Optionally, you can also override the injector configuration for an app by invoking bootstrap with the customProviders argument.
  3. It creates a new Zone and connects it to the angular application's change detection domain instance.
  4. It creates an emulated or shadow DOM on the selected component's host element and loads the template into it.
  5. It instantiates the specified component.
  6. Finally, Angular performs change detection to apply the initial data providers for the application.

Bootstrapping Multiple Applications

When working within a browser window, there are many singleton resources: cookies, title, location, and others. Angular services that represent these resources must likewise be shared across all Angular applications that occupy the same browser window. For this reason, Angular creates exactly one global platform object which stores all shared services, and each angular application injector has the platform injector as its parent.

Each application has its own private injector as well. When there are multiple applications on a page, Angular treats each application injector's services as private to that application.


import 'package:angular/platform/browser.dart';

import 'package:angular_app/app_component.dart';

void main() {
import 'package:angular/angular.dart';
import 'package:angular/platform/browser.dart';
import 'package:angular_tour_of_heroes/app_component.dart';
import 'package:angular_tour_of_heroes/in_memory_data_service.dart';
import 'package:http/http.dart';

void main() {
  bootstrap(AppComponent, [provide(Client, useClass: InMemoryDataService)]
      // Using a real back end?
      // Import browser_client.dart and change the above to:
      // [provide(Client, useFactory: () => new BrowserClient(), deps: [])]

For details concerning these examples see the Quickstart and Tour of Heroes Part 6 documents, respectively.


  • appComponentType: The root component which should act as the application. This is a reference to a Type which is annotated with @Component.
  • customProviders: An additional set of providers that can be added to the app injector to override default injection behavior.

Returns a Future of ComponentRef.


Future<ComponentRef> bootstrap(Type appComponentType, [List customProviders]) =>
    throw new UnsupportedError('''
Using the 'angular2' transformer is required.

Please see for setup instructions,
and ensure your 'pubspec.yaml' file is configured to invoke the 'angular2'
transformer on your application's entry point.''');