Observable.throw replacement in rxjs 5.5.2

问题

I'm migrating to rxjs@5.5.2 and using lettable operators... I also update Observable static methods. I wonder what is the counterpart of Observable.throw and import 'rxjs/add/observable/throw';.

Should I import ugly _throw?

import { _throw } from 'rxjs/observable/throw';

Or there's a better way. Honestly I liked static methods on Observable, and now it seems that all static creating methods like of, from should be imported from rxjs/observable/<methodName> ?

回答1:

I'm still getting my head round 5.5 but it looks like now instead of importing throw use ErrorObservable.

// import { _throw } from 'rxjs/observable/throw';
import { ErrorObservable } from 'rxjs/observable/ErrorObservable';

ErrorObservable.create('error');

From this guide it looks like it has to be _throw to avoid a keyword clash (the rest of the video is good for getting started with 5.5)

回答2:

In continuation to Mick's answer, in the rxjs version 6 _throw is replaced by throwError

 import {Observable, throwError} from 'rxjs';

RxJS Migration Guide

回答3:

Yes _throw is correct(this will do exactly what JayChase wrote but is less code). You do the same with of:

import {of} from 'rxjs/observable/of';
import {_throw} from 'rxjs/observable/throw';

// ...
   // ...
   if (result) {
       return of(result as T);
   } else {
       return _throw('error');
   }
}

回答4:

For Angular 5 and above:

import{Http} from '@angular/http';
import {HttpClient,HttpResponse,HttpErrorResponse  } from '@angular/common/http';
import { Injectable} from '@angular/core'
import {Employee} from './employee';

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


@Injectable() 
export class employeeService{
constructor(private _http:Http){  }
 getEmployees():Observable<Employee[]>{
    return this._http.get('YOUR URL')
                     .pipe(
                         map((res: Response) => res.json()),
                         catchError(this.handleError)
                        );
                     //.pipe(catchError(this.handleError));
 }
 handleError(error:HttpErrorResponse){
    console.log(error);
    return throwError(error.message);
 }    
}

回答5:

If you wonder which one to use - ErrorObservable vs _throw, here's something from the 5.5.2 source core

RxJs library 5.5.2 - throw.ts file

import {  ErrorObservable  } from './ErrorObservable';

export const _throw = ErrorObservable.create;

So, it doesn't matter.

来源：https://stackoverflow.com/questions/47097606/observable-throw-replacement-in-rxjs-5-5-2

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angular

rxjs