Angular2: Find out if FormControl has required validator?

does someone know a way to find out for an Angular2 FormControl if the required validor is registered for the control.

this.form = builder.group({name: ['', Validators.required]};

Can I then query the this.form.controls['name'] control if it is a required field? I know I can check if it is valid, but that's not what I want.

Kind regards, Marc

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.

Angular now provides hasValidator with which you can check if a formcontrol has a sync validator. If you happen to need to check if it has an async validator, that also exist with hasAsyncValidator.

In your case when you want to check if the formcontrol is required, you can do:

this.form.get('name').hasValidator(Validators.required);