Get list of object keys in Angular
import { PipeTransform, Pipe } from "@angular/core"; @Pipe({ name: 'keys' }) export class KeysPipe implements PipeTransform { transform(value, args:string[]) : any { return Object.keys(value); } } Then to get a list of errors for a form element you can do this <ul *ngIf="form.get('userName').invalid" class="help-block with-errors"> <li *ngFor="let error of form.get('userName').errors | keys">{{ error.key }}</li> </ul>