ERROR Error: Uncaught (in promise): NullInjectorError: R3InjectorError(AppModule)[DataService -> HttpClient -> HttpClient -> HttpClient]: code example

Example 1: NullInjectorError: No provider for HttpClient!

import { HttpClientModule } from '@angular/common/http';

Example 2: No provider for HttpClient!

import { HttpClientModule } from '@angular/common/http';