const isBalanced = function (input) {
  let open = ['{', '[', '('];
  let close = ['}', ']', ')'];
  let stack = [];
  for (let i = 0; i < input.length; i++) {
      if (open.indexOf(input[i]) >= 0) {
          stack.push(input[i]);
      } else {
          if (close.indexOf(input[i]) !== open.indexOf(stack.pop())) {
              return false;
          }
      }
  }
  if (stack.length > 0) {
      return false;
  }
  return true;
};

console.log(isBalanced("[[]]")); // true
console.log(isBalanced("[[]"));  // false
console.log(isBalanced("[]]"));  // false