fix: `@IsDateString()` decorator is not validating dates like 2019-02-31

Description

The decorator @IsDateString() is not validating dates like 2019-02-31

Minimal code-snippet showcasing the problem

Here the original source code, please see the big arrow indicating where the error is.

export function isDateString(value: unknown, options?: ValidatorJS.IsISO8601Options): boolean {
  return isISO8601(value, options);
}

/**
 * Alias for IsISO8601 validator
 */
export function IsDateString(
  options?: ValidatorJS.IsISO8601Options,
  validationOptions?: ValidationOptions
): PropertyDecorator {
  return ValidateBy(
    {
      name: IS_DATE_STRING,
      constraints: [options],
      validator: {
        validate: (value, args): boolean => isDateString(value), //<============ HERE THE options argument IS MISSING.
        defaultMessage: buildMessage(
          eachPrefix => eachPrefix + '$property must be a valid ISO 8601 date string',
          validationOptions
        ),
      },
    },
    validationOptions
  );
}

Expected behavior

Invalidates dates like 2019-02-31.

Actual behavior

It doesn’t invalidate dates like 2019-02-31.

[eleazar1595]

@braaar

The arg options can contain params like strict and strictSeparator

The following declared function:

export function isDateString(value: unknown, options?: ValidatorJS.IsISO8601Options): boolean {
  return isISO8601(value, options);
}

Receives the options that will be passed to the function isISO8601(value, options);

Since that function (isDateString) it is called as follow:

validator: {
  validate: (value, args): boolean => isDateString(value), //<============ HERE THE options argument IS MISSING.
  defaultMessage: buildMessage(
    eachPrefix => eachPrefix + '$property must be a valid ISO 8601 date string',
    validationOptions
  ),
}

We can see that isDateString is called with the value only, so at the end, the function isISO8601 won’t receive the necessary options like strick and strictSeparator.

Because of that, the nested validator lib won’t validate wrong dates like 2019-02-31

[NoNameProvided]

This was fixed in 0.14.0. The below snippet now correctly returns a validation error.

import { IsDateString, validate } from 'class-validator';

class MyPayload {
  @IsDateString({ strict: true })
  date: string;

  constructor(date?: string) {
    this.date = date;
  }
}

// This will fail
validate(new MyPayload('2019-02-31')).then(console.log);