backend/src/validators/password.validator.ts

import {
  registerDecorator,
  ValidationOptions,
  ValidatorConstraint,
  ValidatorConstraintInterface,
} from 'class-validator';

@ValidatorConstraint({ async: false })
export class IsPasswordStrongConstraint
  implements ValidatorConstraintInterface
{
  validate(password: string) {
    const regex =
      /^(?=.*[a-z])(?=.*[A-Z])(?=.*\d)(?=.*[!"#$%&'()*+,-./:;<=>?@[\]^_`{|}~])[A-Za-z\d!"#$%&'()*+,-./:;<=>?@[\]^_`{|}~]{8,}$/;
    return regex.test(password);
  }

  defaultMessage() {
    return 'Password must be at least 8 characters long and include at least one uppercase letter, one lowercase letter, one numeric digit, and one special character from the set !"#$%&\'()*+,-./:;<=>?@[\\]^_`{|}~.';
  }
}

export function IsPasswordStrong(validationOptions?: ValidationOptions) {
  return function (object: Record<string, any>, propertyName: string) {
    registerDecorator({
      target: object.constructor,
      propertyName: propertyName,
      options: validationOptions,
      constraints: [],
      validator: IsPasswordStrongConstraint,
    });
  };
}