I'm facing an issue when trying to create a custom validator with Angular. Indeed for my sign-up page, I created a form and to check if password et confirmPassword matched, I wanted to created a custom validator.

But I faced the next issue (see picture), and even all similars requests I found out on Internet, it didn't fix my problem.

Issue is :

import { FormControl, FormGroup, Validators } from '@angular/forms';
import { USER_ATTRIBUTS } from 'src/app/globalVariable';
import { CustomValidators } from 'src/app/validators/custom-validators'

export class UserFormSignUp extends FormGroup{
    constructor(){
        super({firstName: new FormControl('',[
            Validators.required]),
        lastName: new FormControl('',[
            Validators.required]),
        birthdate: new FormControl('',
            Validators.required),
        displayName: new FormControl('',[
            Validators.required,]),
        email: new FormControl('',[
            Validators.required,
            Validators.email]),
        password: new FormControl('',[
            Validators.required]),
        confirmationPassword: new FormControl('',[
            Validators.required])},
        {
            validator: CustomValidators.passwordMatchValidator
        });
}

get firstName() : FormControl{
    return this.get('firstName') as FormControl;
}

get lastName() : FormControl{
    return this.get('lastName') as FormControl;
}

get birthdate() : FormControl{
    return this.get('birthdate') as FormControl;
}

get displayName() : FormControl{
    return this.get('displayName') as FormControl;
}

get email() : FormControl{
    return this.get('email') as FormControl;
}

get password() : FormControl{
    return this.get('password') as FormControl;
}

get confirmationPassword() : FormControl{
    return this.get('confirmationPassword') as FormControl;
}

}

And custom-validators.ts:

import { ValidationErrors, ValidatorFn, AbstractControl } from '@angular/forms';

checkPasswords: ValidatorFn = (group: AbstractControl):  ValidationErrors | null  => { 
    let pass = group.get('password')?.value;
    let confirmPass = group.get('confirmPassword')?.value
    return pass === confirmPass ? null : { notSame: true }
}

}

If you have any idea... I would apreciate.