`returnError` option for `validate` and `validateSync`

Would you accept a PR for a returnError option for validate and validateSync? The default would be false. This would allow people to write their own assertion and validation methods that augment e.message or any part of e without having to wrap validateSync in a try, catch block.

const schema = yup.object().shape({ name: yup.string().required() };)
const validate = (value) => {
  const result = schema.validateSync(value, { returnError: true });
  if (result instanceof Error) {
     result.message = `[mine] ${result.message} for the user data type.`;
  }

  return result;
};

[tecfu]

whats wrong with wrapping in a try catch block? I think throwing an exception is a reasonable interface here, and avoids needing to check if result is an error

Runtime Errors.

A Runtime Error could be thrown from your yup validation call, which the pattern here will always incorrectly handle as a Validation Error.

That’s clunky and a potential security risk for developers for whom it is not obvious to.

Consequently, the recommended usage for yup.validateSync() should actually go something like this:

try {
    yup.validateSync(user)
}
catch (err) {
    if (err.name === 'ValidationError' ) throw new ValidationError(err)         
    throw new Error(err)
}

[jquense]

whats wrong with wrapping in a try catch block? I think throwing an exception is a reasonable interface here, and avoids needing to check if result is an error