How to instantiate an angular 2 service without using the constructor?

Question

I'm trying to use my ApiService class (handling api requests) in another class, but can't get it to work.
The issue is the ApiService constructor needs HttpClient, that means I can't just use something like: http = new ApiService(new HttpClient(), globals)

ApiService:

import { Injectable } from '@angular/core';
import { HttpClient, HttpRequest } from '@angular/common/http';
import { Globals } from './globals';

@Injectable({
  providedIn: 'root'
})
export class ApiService {
  constructor(private http: HttpClient, private globals: Globals) {}

  get(url : string, params: {}){
    return this.http.get(this.globals.api_url.concat(url), {params: params});
  }

  ...
}

Class calling ApiService:

export class UploadAdapter {
    http: ApiService;
    constructor() {}

    upload() {
           //Here I get an error saying can't get post of undefined 
       http.post('api_url'.concat('/medias/upload'), {}, {})
         .subscribe((data) => {
            //do stuff here.
         });
    }



}

To instantiate a class without its constructor sounds like nonsense. — Al Kepp, May 05 '19 at 20:26
https://stackoverflow.com/questions/37482460/getting-instance-of-service-without-constructor-injection — javapedia.net, May 05 '19 at 20:35

score 1 · Answer 1 · answered May 05 '19 at 20:33

1

You are not injecting the service in your component

Your UploadAdapter constructor should be like this

constructor(private http: ApiService) {}

Also you need to use

this.http.post

Instead of

http.post

answered May 05 '19 at 20:33

asimhashmi

4,258
1
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34

Hi Asim, The thing is UploadAdapter isn't a component just another service itself to handle communication with the api. I can't inject the ApiService in the constructor of UploadAdapter, otherwise when instantiating it I need use something in the line of: new UploadAdapter(new ApiService(new HttpClient, new Globals ())) – Soufiane Sakhi May 06 '19 at 20:16

How to instantiate an angular 2 service without using the constructor?

1 Answers1