Angular Forms - Validators

Angular validators

required
requiredTrue
email
min
max
minLength
maxLength
pattern
nullValidator

How to use

Simply add your validations while constructing the FormControl

this.fb.control('',
   [Validators.required, Validators.maxLength(5)])

this.fb.control('',
   Validators.required)

Custom validations


function customerNumberValidator(control: FormControl)
   : { [s: string]: boolean } {
   if (!control.value.match(/^P1000/)) {
      return {invalidCustomerNumber: true};
   }
}

this.fb.control('', customerNumberValidator)

Custom validations over multiple fields


function distinctValueValidator(formArray: FormArray)
   : { [s: string]: boolean } {
   const values = formArray.controls
      .map(control => control.value);
   const uniqueValues = new Set(values);
   if (values.length !== uniqueValues.size) {
      return {notDistinctValues: true};
   }
}

this.fb.array([...], distinctValueValidator)