Imported service is always null

I have the following service imported in my component and somehow it is always null.

This is my appModule:

import { HttpClientModule } from '@angular/common/http';
import { NgModule } from '@angular/core';
import { BrowserModule } from '@angular/platform-browser';
import { AppRoutingModule } from './app-routing.module';
import { AppComponent } from './app.component';

import { TodayComponent } from './components/today/today.component';
import { WeekComponent } from './components/week/week.component';


@NgModule({
  declarations: [
    AppComponent,
    TodayComponent,
    WeekComponent
  ],
  imports: [
    BrowserModule,
    HttpClientModule,
    AppRoutingModule
  ],
  providers: [],
  bootstrap: [AppComponent]
})
export class AppModule { }

My service

import { Injectable } from '@angular/core';
import { Observable } from 'rxjs';
import { HttpClient } from '@angular/common/http';

@Injectable({
  providedIn: 'root'
})

export class TodayService {

  constructor(private http: HttpClient) { }

  public today(object?): Observable<any> {
    return this.http.get(`https://api.openweathermap.org/data/2.5/weather`, { params: object });
  }

}

Component where I use it:

import { TodayService } from '../../services/today.service';

  constructor(
    public todayService: TodayService,
    @Inject(DOCUMENT) private document: Document) {
  }

  public SUB_today: Subscription;
  public success(pos: any) {
    var crd = pos.coords;
    this.SUB_today = this.todayService.today({lat: crd.latitude, lon: crd.longitude, appid: '**************'}).subscribe((res)=>{
      this.today = res;
      this.playingWithBG();
    })
  }

Everything seems correct and I don’t get any errors in the compiler, however whenever I run the code I get:

ERROR TypeError: Cannot read properties of null (reading 'todayService')

Directly linking error with following part of the code: this.SUB_today = this.todayService.today

>Solution :

The error actually says that this is null. So here: this.todayService, you are trying to read null.todayService.

How is that possible that this is null ? Because of the way you call the function success (as detailed in the question comments)

navigator.geolocation.getCurrentPosition(this.success, this.error);

You can either bind this explicitly :

navigator.geolocation.getCurrentPosition(this.success.bind(this), this.error.bind(this));

or provide a lambda :

navigator.geolocation.getCurrentPosition(() => this.success(), () => this.error());