angular2 承诺 observables 和 DI

Question

如果我有这样的服务

import {Injectable} from 'angular2/core';

@Injectable()
export class MyService {

  search(oSrchParams){

    let promise = () =>
    new Promise((resolve, reject) =>
      Meteor.call('mockSearchWS', (error:any, result:any) => error ? reject(error) : resolve(result))
    );

    promise().then(
      (result:Array<Object>) => {
        return result
      },
      (error) => {
        console.log('failed', error);
      }
    )
  }
}

如何在注入时调用并获取值？像这样：

import {Component} from 'angular2/core';
import {MyService} from './my-service';
import 'rxjs/add/operator/map';
import 'rxjs/add/operator/toPromise';

@Component ({
  selector: 'search',
  providers:[MyService]
})

export class App {
  items: Array<string>;
  constructor(private myService: MyService) {
 }

 search(term) {
    // this.myService.search(term).then(items => this.items = items);
    // this.myService.search(term).subscribe()
  }
}

我不确定该服务是否可观察。我见过的大多数例子都使用 http.

Answer 1

您必须return您搜索方法中的承诺：

  search(oSrchParams){

    let promise = () =>
    new Promise((resolve, reject) =>
      Meteor.call('mockSearchWS', (error:any, result:any) => error ? reject(error) : resolve(result))
    );

    return promise().then(
      (result:Array<Object>) => {
        return result
      },
      (error) => {
        console.log('failed', error);
      }
    )
  }
}

这样您就可以在调用此方法的组件中调用 then:

 search(term) {
    this.myService.search(term).then(items => this.items = items);
}

Answer 2

对于任何在这里找到路的人来说，只有几件事。我为方法添加了一个类型

search(oSrchParams): any { ...}

电话变成了

this._searchCall.search(oSrchParams).then(
  (item) => (
    this._ngZone.run(()=>{
      this.items = result,
      (console.log("search", JSON.stringify(this.items)))
    })
  )
);

ngZone 像服务一样注入到构造函数中，并确保对 this.items 的更改反映在浏览器中。我可能有太多 ()，但它有效:-)

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