password and confirmpassword validation in angular using reactive forms

Question

i have attached my code below .im facing problem in adding password mismatch validation.im not getting validation error if i type mismatching password

register.component.html

<div class="form-group row mt-3">
 <label class="col-md-4 col-lg-4 text-center">UserName:<span style="color:red">*</span></label>
<input kendoTextBox required type="text" class="  col-md-6 col-lg-6 form-control " placeholder="Enter Your UserName " formControlName="username"/>
  <div *ngIf="(submitted||f2.username.touched) && f2.username.invalid" class="error-msg">
 <div *ngIf="f2.username.errors.required">UserName  is required</div>
 </div> </div>
 <div class="form-group row">
<label class="col-md-4 col-lg-4 text-center">Password:<span style="color:red">*</span></label>
<input kendoTextBox type="password" required  class="  col-md-6 col-lg-6 form-control " placeholder="Enter Your passowrd " formControlName="password"/>

 <div *ngIf="(submitted||f2.password.touched) && f2.password.invalid" class="error-msg">
<div *ngIf="f2.password.errors.required">password  is required</div>
<div *ngIf="f2.password.errors.minlength">minimum of 6 characters required</div>
    </div>
</div>
<div class="form-group row">
   <label class="col-md-4 col-lg-4 text-center">ConfirmPassword:
<span style="color:red">*</span></label>
<input kendoTextBox required type="password" class="  col-md-6 col-lg-6 form-control " placeholder="Enter Your new password " formControlName="confirmpassword"/>
 <div *ngIf="(submitted||f2.confirmpassword.touched) && f2.confirmpassword.invalid" class="error-msg">
 <div *ngIf="f2.confirmpassword.errors.required"> confirm password  is required</div>  <div *ngIf="f2.confirmpassword.errors.minlength">minimum of 6 characters required
</div>
<div class="error-msg" *ngIf="f2.errors?.mismatch && (f2.controls['confirmpassword'].required || f2.controls['confirmpassword'].touched)">
                              Passwords don't match.
</div>
                          </div>
                      </div>
    enter code here

registercomponent.ts file

here i have used formBuilder.other things are working fine ,only validation for mismatching not working

 this.registerForm3 = this.formBuilder.group({
    username:['', Validators.required],
    password: ['', [Validators.required, Validators.minLength(6)]],
    confirmpassword:['', [Validators.required, Validators.minLength(6)]],
  },
  {validator: this.passwordMatchValidator},
  );

passwordMatchValidator(frm: FormGroup) {
eturn frm.controls['password'].value === 
frm.controls['confirmpassword'].value ? null : {'mismatch': true};
    }
 get f2() { 
    return this.registerForm3.controls; 
  }

Answer 1

I didn't think that you could use a component member function (method) for your custom validator. I assumed it needed to be a function external from your class.

Mine looks like this:

function emailMatcher(c: AbstractControl): { [key: string]: boolean } | null {
  const emailControl = c.get('email');
  const confirmControl = c.get('confirmEmail');

  if (emailControl.pristine || confirmControl.pristine) {
    return null;
  }

  if (emailControl.value === confirmControl.value) {
    return null;
  }
  return { 'match': true };
}

And I attach the validator to a child formGroup like so:

this.customerForm = this.fb.group({
  firstName: ['', [Validators.required, Validators.minLength(3)]],
  lastName: ['', [Validators.required, Validators.maxLength(50)]],
  emailGroup: this.fb.group({
    email: ['', [Validators.required, Validators.email]],
    confirmEmail: ['', Validators.required],
  }, { validator: emailMatcher }),
  phone: ''
});

You could put your validator in a separate file, or in the same file either above or below your component class. Something like this:

function passwordMatchValidator(frm: FormGroup) {
  return frm.controls['password'].value === 
frm.controls['confirmpassword'].value ? null : {'mismatch': true};
}

Then you would define the validator without the this keyword:

{validator: passwordMatchValidator},

You can find the complete example here: https://github.com/DeborahK/Angular-ReactiveForms/tree/master/Demo-Final