angular获取服务器返回信息,Angular/TS-如何将函数从组件调用到服务并获取返回值...

一种方法是实现一个回调,您可以传递方法参数。像这样。

getUserDocInfo(callback) {

this.getUserInfo().then(() => {

this.userDoc = this.afs.doc(`users/${this.userID}`);

this.user = this.userDoc.snapshotChanges();

this.user.subscribe(callback);

})

}

getToken(){

this.userService.getUserDocInfo((value) => {

console.log(value.payload.data());

});

}

你可以退回一个

Observable

也可以在组件上下文中订阅它,并且可以根据需要处理订阅。

import { Observable } from 'rxjs/Observable/';

import 'rxjs/add/observable/fromPromise';

import 'rxjs/add/operator/map';

import 'rxjs/add/operator/mergeMap';

@Injectable()

export class AlertService {

//constructor and properties...

getUserDocInfo(): Observable {

Observable.fromPromise(this.getUserInfo()).mergeMap(() => {

this.userDoc = this.afs.doc(`users/${this.userID}`);

this.user = this.userDoc.snapshotChanges();

return this.user.map(user => user);

});

}

}

@Component(...)

export class MyComponent implements OnDestroy {

subscriptions: Array = new Array;

//constructor

getToken(){

const sub = this.userService.getUserDocInfo().subscribe((value) => {

console.log(value.payload.data());

});

this.subscriptions.push(sub);

}

ngOnDestroy() {

this.subscriptions.forEach(sub => sub.unsubscribe());

}

}