phoxy/ENJS

<%
/* Purpose: supply cascade with data then continue
 * Usage:
 *   __this.CascadeDesign('snippets/data_download', obj);
 * Where object is:
 * {
 *   design: original design that will called as soon scripts ready
 *   source: url location where data would downloaded from
 *   data: (optional) any prepared data
 *   into: (optional) if prepared data exsists, location to append downloaded
 *   from: (optional) ignore any other data supplied from server
 * }
 * Data merging explanation:
 *   Downloaded data is managed to merge with current exsists data
 *   default location of merge is root of data object
 *   And default exsist data is empty object, obviosly
 *   obj.into threated as location in obj.data, and if such location
 *   didnt exsists, it would be created.
 * Data merging example:
 *    data = {'hello': 'world'}
 *    into = 'test.me'
 *    server returned {'ultimate_answer': 42}
 *   After merging design will supplied with
 *    {
 *      'hello' : 'world',
 *      'test' :
 *      {
 *        'me' :
 *        {
 *          'ultimate_answer': 42
 *        }
 *      }
 *    }
 * How it done:
 *   It using local data sequence generation feature
 *   While simulating data digging it requesting server
 *   When ready, merging excisting object with fresh one
 *   By overwriting location mentioned in 'into'.
 * Warning:
 *   If into is empty, on any name collision prepared data has more power
 */

function Merge(a, b, into, from)
{
  if (typeof a !== 'object')
    a = {};
  if (typeof b !== 'object')
    b = {};
  if (typeof into === 'undefined')
    into = "";
  if (typeof from === 'undefined')
    from = "";

  var keys = into.split('.');
  var res = a;

  if (keys.length == 0) // root
  {
    res = {'a': a};
    keys = ['a'];
  }

  while (keys.length > 1)
  {
    var k = keys.pop();

    if (typeof res[k] == 'undefined')
      res[k] = {};

    res = res[k];
  }

  var key = keys.pop();

  var keys = from.split('.');
  var server_object = b;

  while (keys.length)
    server_object = server_object[keys.pop()];

  if (Array.isArray(server_object))
    res[key] = [];
  else
    res[key] = {};


  for (var k in server_object)
    if (server_object.hasOwnProperty(k))
      if (!a.hasOwnProperty(k))
        res[key][k] = server_object[k];

  return a;
}

function DownloadFunctor(cb)
{
  var url = __this.source;

  phoxy.AJAX(url, function(r)
  {
    var data = Merge(__this.data, r.data, __this.into, __this.from);
    cb(data);
  })
}

__this.CascadeDesign(__this.design, DownloadFunctor)

%>