Repeat password validation not working

问题

I am trying to validate password and repeat password in a form. Like this

import { FormGroup, FormBuilder, Validators, AbstractControl } from '@angular/forms';

 this.registerForm = fb.group({
        name: ['', Validators.required],
        email: ['', Validators.compose([Validators.pattern("[A-Z0-9a-z._%+-]+@[A-Za-z0-9.-]+\\.[A-Za-z]{2,64}"), Validators.required])],
        passwords: this.fb.group({
            password: ['', Validators.compose([Validators.required])],
            repassword: ['', Validators.compose([Validators.required])]
          }, this.comparePassword)
    });

function comparePassword(c: AbstractControl) {
return c.get('password').value === c.get(' repassword').value

}

** I also tried passing return false in comparePassword as:

comparePassword(c: AbstractControl) {
      return false;
  }

** but every time console.log(this.registerForm.valid); gives me true, but it should return false if i am giving different inputs in password and repeatpassword. So please help how to resolve this. Thanks in advance

回答1:

A strange thing: custom validation should return null when valid.

If the validation fails you should return a validation error { "comparePassword": true }

So I think your function should be:

comparePassword(control: AbstractControl) {
    if(control.get('password').value === control.get('repassword').value){
        return null;
    }

    return { “comparePassword”: true };
}

Angular.io Custom validation: That function takes an Angular control object and returns either null if the control value is valid or a validation error object. The validation error object typically has a property whose name is the validation key, 'forbiddenName', and whose value is an arbitrary dictionary of values that you could insert into an error message ({name}).

回答2:

This should work

  comparePassword = (control: AbstractControl): {[key: string]: boolean} => {
    // get values
    const password = control.get('password');
    const repassword = control.get('repassword');
    // if no values, validated as true
    if (!password || !repassword) {
      return null;
    }
    // if values match, return null, else nomatch: true
    return password.value === repassword.value ? null : { nomatch: true };
  };

and then in your build of form, set:

{validator: this.comparePassword}

in

this.registerForm = fb.group({
    name: ['', Validators.required],
    email: ['', Validators.compose([Validators.pattern("[A-Z0-9a-z._%+-]+@[A-Za-z0-9.-]+\\.[A-Za-z]{2,64}"), Validators.required])],
    passwords: this.fb.group({
        password: ['', Validators.compose([Validators.required])],
        repassword: ['', Validators.compose([Validators.required])]
      },{validator: this.comparePassword}) // here
});

来源：https://stackoverflow.com/questions/43887201/repeat-password-validation-not-working