providersinangular2.js

import { Component } from '@angular/core';
import { ErrorService } from './errormessage.service';

@Component({
  selector: 'app-root',
  template: `
  <input [(ngModel)]='err' type='text'/>
  <button (click)='setError()'>set error</button>
  `,
  providers: [ErrorService]
})
export class AppComponent {
   constructor(private errorservice: ErrorService) {}
   err: string;
   setError() {
      this.errorservice.logError(this.err);
   }

}