[medium.com]-ngx-crud-02.ts

import { HttpClient, HttpParams } from '@angular/common/http';
import { Injectable } from '@angular/core';
import { Observable } from 'rxjs';
import { RequestBody, ResponseBody } from './example.interface';

import { environment } from '@env';

@Injectable()
export class ExampleService
{
	protected apiUrl : string = environment.apiUrl;
	protected endpoint : string = environment.routes.example;
	
	constructor(protected http : HttpClient)
	{
	}

	findByIdArray(idArray : string[]) : Observable<ResponseBody[]>
	{
		let params : HttpParams = new HttpParams();

		idArray.map(id => params = params.append('id', id));
		return this.http.get<RequestBody[]>(this.apiUrl + this.endpoint,
		{
			params
		});
	}
}