Formbuilder - Change / Remove validation for field based on selected option in form

Ionic Framework ionic-v3
1

Hi,

I’m using the formbuilder with multiple fields where some fields are initially required and some not.

What I struggle is, changing a field to not be required anymore, after some other field in the form has selected a specific value.

For example I got the following form:

this.form = this.formBuilder.group({
      name: ['', Validators.required],
      type: ['', Validators.required],
      year: ['', Validators.required],
      place: ['']
    });

If the user selects value “b” for the field “type”, the field “year” should not have the “Validators.required” option anymore.
Is it possible to do this somehow?

I already searched on google and here, but couldn’t find any good answer.

2

Search “custom validator” or “custom formcontrol.” You need to build your own Validator and put it inside the formGroup.

3

Searched for it and tried some examples, but I was able to get rid of the validation once I initiliazed it for either the one type or the other.
Did now a workaround for it with just passing a “fake” value and making it null while adding to the DB.