docs: function createPartial(func, bitmask, thisArg, partials) {
    var isBind = bitmask & BIND_FLAG,
        Ctor = createCtor(func);
  
    function wrapper() {
      var argsIndex = -1,
          argsLength = arguments.length,
          leftIndex = -1,
          leftLength = partials.length,
          args = Array(leftLength + argsLength),
          fn = this && this !== root && this instanceof wrapper ? Ctor : func;
  
      while (++leftIndex < leftLength) {
        args[leftIndex] = partials[leftIndex];
      }
      while (argsLength--) {
        args[leftIndex++] = arguments[++argsIndex];
      }
      return apply(fn, isBind ? thisArg : this, args);
    }
    return wrapper;
  }