Map doesn't exist on Observable<Object> with angular 6.0.0 and rxjs 6.1.0

Question

Hi I'm trying to follow a tutorial on angular but the tutorial was made in September. I believe the person used angular-cli 1.3.2. I'm not sure which version of rxjs he was using. I'm using angular cli 6.0.0 and angular 6 with rxjs 6.1.0.

I am running into a problem where calling .map on observable is not found. ERROR in xxx/xxx/dataService.ts(19,14): error TS2339: Property 'map' does not exist on type 'Observable<Object>'. I looked into the Observable class and I don't see a function called map.

Is there a new way in angular 6 or rxjs to achieve what the tutorial is trying to do?

Here is my .ts file:

import { HttpClient } from "@angular/common/http";
import { Injectable } from "@angular/core";
import { map } from 'rxjs/operators';

@Injectable()
export class DataService {

    constructor(private http: HttpClient) {

    }

    public products = [

    ];

    loadProducts() {
        return this.http.get("/api/products")
            .map((data: any[]) => {
                this.products = data;
                return true;
            });
    }
}

This is the output from ng --version

λ ng --version

     _                      _                 ____ _     ___
    / \   _ __   __ _ _   _| | __ _ _ __     / ___| |   |_ _|
   / △ \ | '_ \ / _` | | | | |/ _` | '__|   | |   | |    | |
  / ___ \| | | | (_| | |_| | | (_| | |      | |___| |___ | |
 /_/   \_\_| |_|\__, |\__,_|_|\__,_|_|       \____|_____|___|
                |___/


Angular CLI: 6.0.0
Node: 8.11.1
OS: win32 x64
Angular: 6.0.0
... animations, common, compiler, compiler-cli, core, forms
... http, language-service, platform-browser
... platform-browser-dynamic, router

Package                           Version
-----------------------------------------------------------
@angular-devkit/architect         0.6.0
@angular-devkit/build-angular     0.6.0
@angular-devkit/build-optimizer   0.6.0
@angular-devkit/core              0.6.0
@angular-devkit/schematics        0.6.0 (cli-only)
@ngtools/webpack                  6.0.0
@schematics/angular               0.6.0 (cli-only)
@schematics/update                0.6.0 (cli-only)
rxjs                              6.1.0
typescript                        2.7.2
webpack                           4.6.0

I did a little digging and in my node_modules/rxjs/observable folder there is no map.* file

λ ls -R rxjs\observable
'rxjs\observable':
ArrayLikeObservable.d.ts            IfObservable.d.ts             combineLatest.d.ts       if.js.map
ArrayLikeObservable.js              IfObservable.js               combineLatest.js         interval.d.ts
ArrayLikeObservable.js.map          IfObservable.js.map           combineLatest.js.map     interval.js
ArrayObservable.d.ts                IntervalObservable.d.ts       concat.d.ts              interval.js.map
ArrayObservable.js                  IntervalObservable.js         concat.js                merge.d.ts
ArrayObservable.js.map              IntervalObservable.js.map     concat.js.map            merge.js
BoundCallbackObservable.d.ts        IteratorObservable.d.ts       defer.d.ts               merge.js.map
BoundCallbackObservable.js          IteratorObservable.js         defer.js                 never.d.ts
BoundCallbackObservable.js.map      IteratorObservable.js.map     defer.js.map             never.js
BoundNodeCallbackObservable.d.ts    NeverObservable.d.ts          dom/                     never.js.map
BoundNodeCallbackObservable.js      NeverObservable.js            empty.d.ts               of.d.ts
BoundNodeCallbackObservable.js.map  NeverObservable.js.map        empty.js                 of.js
ConnectableObservable.d.ts          PairsObservable.d.ts          empty.js.map             of.js.map
ConnectableObservable.js            PairsObservable.js            forkJoin.d.ts            onErrorResumeNext.d.ts
ConnectableObservable.js.map        PairsObservable.js.map        forkJoin.js              onErrorResumeNext.js
DeferObservable.d.ts                PromiseObservable.d.ts        forkJoin.js.map          onErrorResumeNext.js.map DeferObservable.js                  PromiseObservable.js          from.d.ts                pairs.d.ts
DeferObservable.js.map              PromiseObservable.js.map      from.js                  pairs.js
EmptyObservable.d.ts                RangeObservable.d.ts          from.js.map              pairs.js.map
EmptyObservable.js                  RangeObservable.js            fromArray.d.ts           race.d.ts
EmptyObservable.js.map              RangeObservable.js.map        fromArray.js             race.js
ErrorObservable.d.ts                ScalarObservable.d.ts         fromArray.js.map         race.js.map
ErrorObservable.js                  ScalarObservable.js           fromEvent.d.ts           range.d.ts
ErrorObservable.js.map              ScalarObservable.js.map       fromEvent.js             range.js
ForkJoinObservable.d.ts             SubscribeOnObservable.d.ts    fromEvent.js.map         range.js.map
ForkJoinObservable.js               SubscribeOnObservable.js      fromEventPattern.d.ts    throw.d.ts
ForkJoinObservable.js.map           SubscribeOnObservable.js.map  fromEventPattern.js      throw.js
FromEventObservable.d.ts            TimerObservable.d.ts          fromEventPattern.js.map  throw.js.map
FromEventObservable.js              TimerObservable.js            fromIterable.d.ts        timer.d.ts
FromEventObservable.js.map          TimerObservable.js.map        fromIterable.js          timer.js
FromEventPatternObservable.d.ts     UsingObservable.d.ts          fromIterable.js.map      timer.js.map
FromEventPatternObservable.js       UsingObservable.js            fromPromise.d.ts         using.d.ts
FromEventPatternObservable.js.map   UsingObservable.js.map        fromPromise.js           using.js
FromObservable.d.ts                 bindCallback.d.ts             fromPromise.js.map       using.js.map
FromObservable.js                   bindCallback.js               generate.d.ts            zip.d.ts
FromObservable.js.map               bindCallback.js.map           generate.js              zip.js
GenerateObservable.d.ts             bindNodeCallback.d.ts         generate.js.map          zip.js.map
GenerateObservable.js               bindNodeCallback.js           if.d.ts
GenerateObservable.js.map           bindNodeCallback.js.map       if.js

'rxjs\observable/dom':
AjaxObservable.d.ts  AjaxObservable.js.map  WebSocketSubject.js      ajax.d.ts  ajax.js.map     webSocket.js
AjaxObservable.js    WebSocketSubject.d.ts  WebSocketSubject.js.map  ajax.js    webSocket.d.ts  webSocket.js.map

Answer 1

In rxjs@6 you can use from as standalone function:

import { from } from 'rxjs';

See also migration to rxjs6 guide

https://github.com/ReactiveX/rxjs/blob/master/docs_app/content/guide/v6/migration.md#import-paths

UPDATE

You need to switch to pipe syntax, make sure you import all operators used from rxjs/operators. For example:

import { map, filter, catchError, mergeMap } from 'rxjs/operators';

DOCUMENTATION

Answer 2

pipe is a method on Observable which is used for composing operators

Here is the way how you can use the new method pipe() in Version 6:

loadProducts() {
    return this.http.get("/api/products").
        pipe(
           map((data: any[]) => {
             this.products = data;
             return true;
           }), catchError( error => {
             return throwError( 'Something went wrong!' )
           });
        )
}

Keep in mind that with Version 6 you should now use catchError and throwError instead of:catch and throw. Here is the correct import with Version 6:

import { Observable, of, throwError, ...} from "rxjs"

import { map, catchError, ...} from "rxjs/operatros"