Angular2: Find out if FormControl has required validator?

This function should work for FormGroups and FormControls

  export const hasRequiredField = (abstractControl: AbstractControl): boolean => {    if (abstractControl.validator) {        const validator = abstractControl.validator({}as AbstractControl);        if (validator && validator.required) {            return true;        }    }    if (abstractControl['controls']) {        for (const controlName in abstractControl['controls']) {            if (abstractControl['controls'][controlName]) {                if (hasRequiredField(abstractControl['controls'][controlName])) {                    return true;                }            }        }    }    return false;};

While there is no Angular API to directly find if the required validator is set for a particular field, the roundabout way to achieve this is like as below:

import { NgForm, FormControl } from '@angular/forms';const isRequiredControl = (formGroup: NgForm, controlName: string): boolean => {    const { controls } = formGroup    const control = controls[controlName]    const { validator } = control    if (validator) {        const validation = validator(new FormControl())        return validation !== null && validation.required === true    }    return false}

I have tested this and this triggers only if the Validator.Required validator is added to the particular FormControl.

There is no method how to check validators or get all validators: https://github.com/angular/angular/issues/13461

@fairlie-agile solution is pretty clever. But I think we have to use empty FormControl because we need fire required validator and this.group.controls[this.config.name] could be already initialized with some value.

ngOnInit() {    let formControl = this.group.controls[this.config.name];    let errors: any = formControl.validator && formControl.validator(new FormControl());    this._required = errors !== null && errors.required;}