Question

我想使用Promise运算符

首先我加入了rxjs：

import 'rxjs/add/operator/toPromise';

然后在我的组件中，我用它

ngOnInit() {
    this.EJnames= this.dataservice.getResults();
    this.generalinfosservice.getResults("nothing").then(data=>{this.data=data; console.log(data)}); //Log 1
 console.log(this.data); // log 2
  }

我收到了这个错误

ERROR TypeError: this.generalinfosservice.getResults(...).toPromise is not a function

我已经检查过Package.json我有rxjs：

"rxjs": "^5.1.0",

这是generalinfosservice.getresults功能

import { Injectable } from '@angular/core';
import { RmpmService}  from '../../shared/abstract-classes/service'
import { HttpClient } from '@angular/common/http';

@Injectable()
export class GeneralinfosService extends RmpmService {

  constructor(public httpClient: HttpClient) { }
    public getResults(body) {
        let url;
        let mockUrl
            url = '/obtenirNomenclatures/typeNomenclatures/';
            mockUrl = 'assets/data/group.json';

    return this.post(url, mockUrl, body);
    }
}

并发布一个抽象类中的函数：

post( url, mockUrl, body) {
    if( environment.mocked ) {
        return this.httpClient.get( mockUrl ).toPromise().then( data => { return data} );
    } else {
        return this.httpClient.post( url, JSON.stringify( body ) )
            .toPromise()
            .then( data => {
                return data;
            }, ( err: any ) => {
                return this.handleError( err.message );
            } );
    }
}

PS：我在嘲笑环境

Answer 1

您在this.post()中呼叫getResults()。这将在您的班级（GeneralInfoService）中查找名为post()的方法。

您实际需要致电的是this.httpClient.post()。

Answer 2

// Need to import this for my fixes below to work:
import { Observable } from 'rxjs/Observable';

// Your current "post" method.
post( url, mockUrl, body) {
    if( environment.mocked ) {
        // In your promise, you are not returning another promise. You are returning only the "data" value, which doesn't have a ".then()" function associated to it.
        // return this.httpClient.get( mockUrl ).toPromise().then( data => { return data} );
        
        // Here is how you should do it:
        return this.httpClient.get( mockUrl )
            .toPromise()
            .then(( data ) => Observable.of( data ).toPromise());
    } else {
        return this.httpClient.post( url, JSON.stringify( body ) )
            .toPromise()
            .then(
                ( data ) => Observable.of( data ).toPromise(), 
                ( err: any ) => this.handleError( err.message )
            );
    }
}

导入rxjs后，toPromise不是一个函数

2 个答案: