Angular 5 Core module service undefined in feature module

Question

I'm following the style guide in an Angular 5 project, and I am trying to implement the hardest part of the style guide (core/shared modules). So I want my Core Module to provide a singleton service that is used in all my app. The service is just a wrapper for LocalStorage. So, I created the CoreModule, and added the service to the providers array like this:

CoreModule

import { NgModule, Optional, SkipSelf } from '@angular/core';
import { CommonModule } from '@angular/common';

import { LocalStorageService } from './local-storage.service';

@NgModule({
  imports: [
    CommonModule,
  ],
  exports: [
    CommonModule,
  ],
  providers: [ LocalStorageService ],
  declarations: [ ]
})
export class CoreModule {
  constructor( @Optional() @SkipSelf() parentModule: CoreModule) {
    if (parentModule) {
      throw new Error('CoreModule has already been loaded. You should only import Core modules in the AppModule only.');
    }
  }
}

MyLazyComponent

import { Component, OnInit, Input, Output, ViewChild } from '@angular/core';

import { LocalStorageService } from '@app/core/local-storage.service';

@Component({
  selector: 'app-my-lazy',
  templateUrl: './my-lazy.component.html',
  styleUrls: ['./my-lazy.component.scss']
})
export class MyLazyComponent implements OnInit {

  constructor(private localStorageService: LocalStorageService) { }

  ngOnInit() {
    this.debounceValues();
  }

  inputChange(data) {
    this.localStorageService.setItem('saveData', data);
  }

  debounceValues() {
    this.form.valueChanges
      .debounceTime(1000)
      .distinctUntilChanged()
      .subscribe(this.inputChange);
  }
}

After that, I wanted to use the LocalStorageService in a feature module, so I imported it, and injected it in the constructor using the normal DI way. Unfortunately I get TypeError: this.localStorageService is undefined

What I missed ? Thanks in advance

Answer 1

Well as mentioned in the question's comment, that was a JavaScript context issue not an Angular one, so I changed the inputChange method to using the ES6 arrow function feature and it worked like charm.