function createChainedFunction() {
  for (var _len = arguments.length, funcs = new Array(_len), _key = 0; _key < _len; _key++) {
    funcs[_key] = arguments[_key];
  }

  return funcs.filter(function (f) {
    return f != null;
  }).reduce(function (acc, f) {
    if (typeof f !== 'function') {
      throw new Error('Invalid Argument Type, must only provide functions, undefined, or null.');
    }

    if (acc === null) return f;
    return function chainedFunction() {
      for (var _len2 = arguments.length, args = new Array(_len2), _key2 = 0; _key2 < _len2; _key2++) {
        args[_key2] = arguments[_key2];
      }

      acc.apply(this, args);
      f.apply(this, args);
    };
  }, null);
}
Safe chained function

Will only create a new function if needed,
otherwise will pass back existing functions or null.

@param {function} functions to chain
@returns {function|null}