[Angular] Using InjectionToken

转载于 2017-05-11 01:35:00 发布 · 104 阅读

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原文链接：http://www.cnblogs.com/Answer1215/p/6839031.html

文章标签：

#javascript #json #ViewUI

本文介绍了Angular中InjectionToken的使用方法及其与OpaqueToken的区别。InjectionToken允许开发者在依赖注入过程中传递类型信息，提供了更灵活的配置选项。文章通过示例展示了如何定义InjectionToken并将其应用于模块和服务中。

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Previously we have 'OpaqueToken', but it is DEPRECATED. The new one is called 'InjectionToken'.

The difference between OpaqueToken is for InjectionToken we are able to pass the type, but OpaqueToken not.

// token.ts

import { InjectionToken } from '@angular/core';

export const API_TOKEN = new InjectionToken<string>('api');

//app.module.ts

  providers: [
    { provide: API_TOKEN, useValue: '/api/pizzas' }
  ]

// service.ts

import { API_TOKEN } from './token';

@Injectable()
export class FoodService {
  constructor(
    private http: Http,
    @Inject(API_TOKEN) private api: string
  ) {}
  getFood(): Observable<any[]> {
    return this.http.get(this.api)
      .map(response => response.json());
  }
}