Flatten a multi dimentional array

gistfile1.txt

const flatten = (...args) => {
  let result = [];
  args.forEach(arg => {
    if (Array.isArray(arg)) {
      arg.forEach(element => {
        if (Array.isArray(element)) {
          result = result.concat(flatten(element));
        } else {
          result.push(element);
        }
      });
    } else {
      result.push(arg);
    }
  });
  return result;
};