StaticInjectorError(AppModule)[AppComponent -> DataService] - node.js

Question

I have been following tutorials on setting up a mean stack, yet when running my code on localhost I get a blank screen with the error 'StaticInjectorError(AppModule)[DataService -> Http]:'. I've spent two days trying to figure out this bug, and couldn't find anything.
As for details on the tools I'm using, Angular 8.3.17, node v12
data.service.ts
import { Injectable } from '#angular/core';
import { Http, Headers, RequestOptions } from '#angular/http';
import 'rxjs/add/operator/map';
#Injectable()
export class DataService {
result:any;
constructor(private _http: Http) { }
getAccounts() {
return this._http.get("/api/accounts")
.map(result => this.result = result.json().data);
}
}
app.module.ts
import { BrowserModule } from '#angular/platform-browser';
import { NgModule } from '#angular/core';
import { AppRoutingModule } from './app-routing.module';
import { AppComponent } from './app.component';
// Import the Http Module and our Data Service
import { HttpModule } from '#angular/http';
import { DataService } from './data.service';
#NgModule({
declarations: [
AppComponent
],
imports: [
BrowserModule,
AppRoutingModule
],
providers: [],
bootstrap: [AppComponent]
})
export class AppModule { }
app.component.ts
import { Component } from '#angular/core';
// Import the DataService
import { DataService } from './data.service';
#Component({
selector: 'app-root',
templateUrl: './app.component.html',
styleUrls: ['./app.component.css']
})
export class AppComponent {
// Define a users property to hold our user data
accounts: Array<any>;
// Create an instance of the DataService through dependency injection
constructor(private _dataService: DataService) {
// Access the Data Service's getUsers() method we defined
this._dataService.getAccounts()
.subscribe(res => this.accounts = res);
}
}

Answer 1

You need to add DataService in providers part of app.module.ts file like this
providers: [DataService],

Answer 2

I found the problem, I had to add dataService to my providers array, and HttpModule to imports.
#NgModule({
declarations: [
AppComponent
],
imports: [
BrowserModule,
HttpModule,
AppRoutingModule
],
providers: [DataService],
bootstrap: [AppComponent]
})