提供Angular 7服务：'root'

Question

I'm very new to angular development so please forgive me if this is a very basic question

But I have a cart service which I have at the moment simply has a simple console log function

 import { Injectable } from '@angular/core'; @Injectable({ providedIn: 'root' }) export class CartService { constructor( ) {} public addItem() { console.log('Hello'); } } 

and basically I cannot figure out how to use this service within a NG Module that I have installed , I have successfully used it in other components via the constructor but the ngmodule doesn't have this?

I get the fact that it's a singleton at the app-module level by using the providedIn: 'root' tag added in angular 6

but just can't figure out how to call cartService.addItem()?

Thanks if anyone can help!

Answer 1

You can use Dependency Injection like this to call the service

export class AppComponent {
  constructor(private cartService: CartService) {

  }

  doSomething() {
     this.cartService.addItem();
  }
}

Answer 2

Below is the sample code of how to use service in component:

Component.ts

import { Component, OnInit} from '@angular/core';
import { yourSeerviceName } from "PATH_TO_SERVICE";
@Component({
    selector: 'app-dummy',
    styleUrls: ['dummy.component.sass'],
    templateUrl: 'dummy.component.html'
})


export class yourComponent implements OnInit {
    // you can provide any name for variable it's upto you
    constructor(private dummyService:yourSeerviceName) {

    }

    //access the method in you'r service by performing below action.
    this.dummyService.yourMethod();
}

Answer 3

If you created a new module, you need to introduce the service to your module, by going to the .module.ts file and adding your service to the providers array. It will be something like:

providers: [
    CartService
  ],