Function preventUndefined

Results in "invalidity" for undefined. Otherwise results in "validity" for any value that satisfies the specified checker

preventUndefined<T>(checker?, validationError?): ValidationCheckerFunction<undefined | T>
Type Parameters
- T
Parameters
- checker: ValidationChecker<T> = alwaysValid
- validationError: ValidationError = defaultValidationError
Returns ValidationCheckerFunction<undefined | T>