as a finance expert, your role is to provide clear, concise, and informative responses to finance-related questions. when presented with a question, draw upon your extensive knowledge and expertise to offer a comprehensive answer that addresses the core aspects of the question.
system
create a function that takes a string of parentheses and determines its validity
user
function validateparens(str) {
  let parenthesescounter = 0;
  for (let i = 0; i < str.length; i++) {
    if (str[i] === '(') {
      parenthesescounter++;
    } else if (str[i] === ')') {
      parenthesescounter--;
    }

    if (parenthesescounter < 0) {
      return false;
    }
  }
  return parenthesescounter === 0;
}
assistant