1  // API
 2  module.exports = state;
 3  
 4  /**
 5   * Creates initial state object
 6   * for iteration over list
 7   *
 8   * @param   {array|object} list - list to iterate over
 9   * @param   {function|null} sortMethod - function to use for keys sort,
10   *                                     or `null` to keep them as is
11   * @returns {object} - initial state object
12   */
13  function state(list, sortMethod)
14  {
15    var isNamedList = !Array.isArray(list)
16      , initState =
17      {
18        index    : 0,
19        keyedList: isNamedList || sortMethod ? Object.keys(list) : null,
20        jobs     : {},
21        results  : isNamedList ? {} : [],
22        size     : isNamedList ? Object.keys(list).length : list.length
23      }
24      ;
25  
26    if (sortMethod)
27    {
28      // sort array keys based on it's values
29      // sort object's keys just on own merit
30      initState.keyedList.sort(isNamedList ? sortMethod : function(a, b)
31      {
32        return sortMethod(list[a], list[b]);
33      });
34    }
35  
36    return initState;
37  }