How to write Helper class in typescript? [duplicate]

Answer 1

First of all class Helper should be a service class HelperClass, which should be injectable.

import {Injectable} from "@angular/core";
import {Http} from "@angular/http";
import {TranslateService} from "ng2-translate";

@Injectable()
export class HelperService {
   constructor(private http: Http, private translateService: TranslateService) {

   }

}

Now you can simply inject this helper and use it in any component you like.

import {HelperService} from "./helper.service.ts";
@Component({
   ...
})
export class MyComponent{
   constructor(public helperService: HelperService) {}
}

Update: You need to add the service in providers array of the root module for it to work, or for angular6+, the service can be provided as follows

@Injectable({
  providedIn: 'root'
})
export class HelperService {
   ...
}