Evaluates a regex on the type of input and validates if matches.
Valid values:
validator.typeOf(/boolean/).validate(true);
validator.typeOf(/number/).validate(1);
validator.typeOf(/object/).validate({});
validator.typeOf(/string/).validate('foo');
Invalid values:
validator.typeOf(/boolean/).validate('foo');
validator.typeOf(/number/).validate({});
validator.typeOf(/object/).validate(1);
validator.typeOf(/string/).validate(true);
Throw error if the regex is invalid:
validator.typeOf({}).validate('foo'); // Error('Invalid RegExp.')