//'some-string'.validate('!empty') === true
//'some-string'.validate('length>30') === false
//'some-string'.validate('!length<=10') === true
//'some-string'.validate('length==3') === false
//'some-string'.validate(/^.*-s/i) === true

const validate = (str) => {
  let result = false;
  if (str === "" || str.length > 29 || str.length === 3) {
    result = !result;
  }
  if (str.match(/^.*-s/i)) {
    result = true;
  }
  return result;
}

validate("sSfffff");