/*
 *  Object.assign(), described in E6 Section 19.1.2.1
 *
 *  https://people.mozilla.org/~jorendorff/es6-draft.html#sec-object.assign
 */

if (typeof Object.assign === 'undefined') {
   Object.defineProperty(Object, 'assign', {
       value: function (target) {
           var i, n, j, m, k;
           var source, keys;
           var gotError;
           var pendingError;

           if (target == null) {
               throw new Exception('target null or undefined');
           }

           for (i = 1, n = arguments.length; i < n; i++) {
               source = arguments[i];
               if (source == null) {
                   continue;  // null or undefined
               }
               source = Object(source);
               keys = Object.keys(source);  // enumerable own keys

               for (j = 0, m = keys.length; j < m; j++) {
                   k = keys[j];
                   try {
                       target[k] = source[k];
                   } catch (e) {
                       if (!gotError) {
                           gotError = true;
                           pendingError = e;
                       }
                   }
               }
           }

           if (gotError) {
               throw pendingError;
           }
       }, writable: true, enumerable: false, configurable: true
   });
}