Angular 4 remove required validator conditionally

Question

In Angular 4 app I have a form model like this:

this.form = this._fb.group({
    title: [\'\', [Validators.required, Validators.minLength(3), Validators.maxLengt         


        

Answer 1

Use empty array to remove all existing validators.

this.frmFeasibility.controls['pop_name'].setValidators([]);
this.frmFeasibility.controls['pop_name'].updateValueAndValidity();

Answer 2

if you want to add validation try this one.

saveDraft() {
   this.form.get('title').setValidators([Validators.required, Validators.minLength(3)]);
   this.form.get('title').updateValueAndValidity();
}

if you want to remove validators try this one.

saveDraft() {
 this.form.get('title').clearValidators();
 this.form.get('title').updateValueAndValidity();
}

Answer 3

To Add Validators:

this.form = this._fb.group({
    title: ['', [Validators.required, Validators.minLength(3), Validators.maxLength(50)]],
    description: ['', [Validators.required, Validators.minLength(3)]]
});

or

this.form.get('title').setValidators([Validators.required,Validators.minLength(3), Validators.maxLength(50)]);

To Remove the 'Required' validator only, you can reset the validators.

saveDraft() {
     this.form.get('title').setValidators([Validators.minLength(3), Validators.maxLength(50)]);
     this.form.get('title').updateValueAndValidity();
}

updateValueAndValidity determines how the control propagates changes and emits events when the value and validators are changed

Answer 4

saveDraft() {
   this.form.get('title').setValidators([Validators.required, Validators.minLength(3)]);
   this.form.get('title').updateValueAndValidity();
}

saveDraft() {
 this.form.get('title').clearValidators();
 this.form.get('title').updateValueAndValidity();
}