相关疑难解决方法(0)

这是一个基本的TypeScript/ES.next示例,它使用DI的装饰器,并遵循框架手册建议的语法:

import {Component, Inject, Injectable, NgModule, OpaqueToken} from '@angular/core';
import {BrowserModule} from '@angular/platform-browser';
import {platformBrowserDynamic} from '@angular/platform-browser-dynamic';

const CONSTANT = { value: 'constant' };
const CONSTANT_TOKEN = new OpaqueToken;
const CONSTANT_PROVIDER = { provide: CONSTANT_TOKEN, useValue: CONSTANT };

@Injectable()
class Service {
  constructor(@Inject(CONSTANT_TOKEN) constant) {
    console.log('Service constructor', constant);
  }
}

@Component({
  selector: 'app',
  template: '...',
  providers: [Service, CONSTANT_PROVIDER]
})
class AppComponent {
  constructor(@Inject(Service) service: Service, @Inject(CONSTANT_TOKEN) constant) {
    console.log('AppComponent constructor', service, constant);    
  }
}

@NgModule({
  imports: [BrowserModule],
  declarations: [AppComponent],
  bootstrap: …