错误TS2339:类型'Observable <any>'上不存在属性'catchError'

时间:2018-05-30 09:12:57

标签: angular angular-services

这是我在book.service.ts中的代码:

import { Injectable } from '@angular/core';
import { Http, Response } from '@angular/http';
import {Observable} from 'rxjs';
import { Book } from './book';
import { map } from "rxjs/operators";
import { catchError } from 'rxjs/operators';

//import { Component, OnInit } from '@angular/core';
//import {HttpClient} from "@angular/common/http";
//import { Observable } from 'rxjs/Observable'; 
//import 'rxjs/add/operator/map';
//import 'rxjs/add/operators/catch';
//import 'rxjs/operators/toPromise';

@Injectable()
export class BookService 
{
    url = "http://localhost:4200/assets/data/books.json";

    constructor(private http:Http) { }

    getBooksWithObservable(): Observable<Book[]> 
    {
        return this.http.get(this.url)
                .pipe(map(this.extractData))
                .catchError(this.handleErrorObservable);
    }
    getBooksWithPromise(): Promise<Book[]> 
    {
        return this.http.get(this.url).toPromise()
            .then(this.extractData)
            .catch(this.handleErrorPromise);
    }
    private extractData(res: Response) 
    {
        let body = res.json();
        return body;
    }
    private handleErrorObservable (error: Response | any) 
    {
        console.error(error.message || error);
        //console.log("Error in Observable");
        return Observable.throw(error.message || error);
    }
    private handleErrorPromise (error: Response | any) 
    {
        console.error(error.message || error);
        return Promise.reject(error.message || error);
    }   
}

我在这里得到错误:

  

src / app / book.service.ts(26,18)中的错误:错误TS2339:类型'Observable'上不存在属性'catchError'。

错误在第26行,即:

.catchError(this.handleErrorObservable); 

我尝试过很多东西,但没有任何效果......任何人都可以解决这个问题吗?

用'catch'做了但是没有用,所以我去了'catchError'但是仍然有这个错误......

4 个答案:

答案 0 :(得分:6)

catchError需要导入,然后在.pipe中使用:

import {catchError} from 'rxjs/operators/catchError'; 

return this.http.get(this.url)
            .pipe(
              map(this.extractData),
              catchError(this.handleErrorObservable)
            );

答案 1 :(得分:3)

您需要在pipe内使用它,如下所示:

getBooksWithObservable(): Observable<Book[]> {
  return this.http.get(this.url)
             .pipe(map(this.extractData),catchError(this.handleErrorObservable));
}

答案 2 :(得分:1)

catchError必须位于pipe

 import { Observable, pipe } from 'rxjs';
 import { map, catchError } from 'rxjs/operators';

 getBooksWithObservable(): Observable<Book[]> 
    {
        return this.http.get(this.url)
                .pipe(
                   map(this.extractData),
                   catchError(this.handleErrorObservable)
                 );                    
    }

答案 3 :(得分:-1)

您必须更改为:

...
return this.http.get(this.url).subscribe((r:Author)=>console.log("GOOD"),err=>console.log("ERROR))
...

这是rxjs的问题