angular - Observable.of は正しいインポートを持つ関数ではありません

Question

angular 6でオブザーバブルの「of」メソッドのインポートに問題があります。プロジェクトを新しくインストールし、すべての更新されたパッケージを使用しても、まだエラーが発生します。だから、私は小さなプロジェクトを作りました

これが提供するサービスです

import { Injectable } from '@angular/core';
import { TableRow } from './table-row';
import { Observable, of } from 'rxjs';

@Injectable({
  providedIn: 'root'
})
export class TestTableService {

  private testData : TableRow[] = [
    {id:1, name:'pi', value:3.14},
    {id:2, name:'euler', value:2.71},
    {id:3, name:'Feigenbaum constant', value:2.50290},
    {id:4, name:'Mills constant', value:1.30637},
    {id:5, name:'one', value:1},
    {id:6, name:'square root of 2', value:1.41421}
  ];

  constructor() { }

  public getData() : Observable<TableRow[]>
  {
    return Observable.of(this.testData);
  }
}

これはそれを使用するコンポーネントです:

import { Component, OnInit } from '@angular/core';
import { TestTableService } from './../test-table.service';
import { TableRow } from './../table-row';

@Component({
  selector: 'app-test-table',
  templateUrl: './test-table.component.html',
  styleUrls: ['./test-table.component.css']
})
export class TestTableComponent implements OnInit {
  tableData : TableRow[] = [];

  constructor(private testTable : TestTableService) { }

  ngOnInit() {
    this.testTable.getData()
      .subscribe(table => this.tableData = table);
  }

}

インポートは他の質問とすべて同じであることに注意してください

プロジェクト package.json:

{
  "name": "angular-table-test",
  "version": "0.0.0",
  "scripts": {
    "ng": "ng",
    "start": "ng serve",
    "build": "ng build",
    "test": "ng test",
    "lint": "ng lint",
    "e2e": "ng e2e"
  },
  "private": true,
  "dependencies": {
    "@angular/animations": "^6.0.2",
    "@angular/cdk": "^6.1.0",
    "@angular/common": "^6.0.2",
    "@angular/compiler": "^6.0.2",
    "@angular/core": "^6.0.2",
    "@angular/forms": "^6.0.2",
    "@angular/http": "^6.0.2",
    "@angular/material": "^6.1.0",
    "@angular/platform-browser": "^6.0.2",
    "@angular/platform-browser-dynamic": "^6.0.2",
    "@angular/router": "^6.0.2",
    "core-js": "^2.5.4",
    "hammerjs": "^2.0.8",
    "rxjs": "^6.0.0",
    "zone.js": "^0.8.26"
  },
  "devDependencies": {
    "@angular/compiler-cli": "^6.0.2",
    "@angular-devkit/build-angular": "~0.6.3",
    "typescript": "~2.7.2",
    "@angular/cli": "~6.0.3",
    "@angular/language-service": "^6.0.2",
    "@types/jasmine": "~2.8.6",
    "@types/jasminewd2": "~2.0.3",
    "@types/node": "~8.9.4",
    "codelyzer": "~4.2.1",
    "jasmine-core": "~2.99.1",
    "jasmine-spec-reporter": "~4.2.1",
    "karma": "~1.7.1",
    "karma-chrome-launcher": "~2.2.0",
    "karma-coverage-istanbul-reporter": "~1.4.2",
    "karma-jasmine": "~1.1.1",
    "karma-jasmine-html-reporter": "^0.2.2",
    "protractor": "~5.3.0",
    "ts-node": "~5.0.1",
    "tslint": "~5.9.1"
  }
}

何が問題なのですか？