Function baseMerge

lodash.js:3643–3663

* The base implementation of `_.merge` without support for multiple sources. * * @private * @param {Object} object The destination object. * @param {Object} source The source object. * @param {number} srcIndex The index of `source`. * @param {Function} [customizer] The

(object, source, srcIndex, customizer, stack)

     *  counterparts.
     */
    function baseMerge(object, source, srcIndex, customizer, stack) {
      if (object === source) {
        return;
      }
      baseFor(source, function(srcValue, key) {
        stack || (stack = new Stack);
        if (isObject(srcValue)) {
          baseMergeDeep(object, source, key, srcIndex, baseMerge, customizer, stack);
        }
        else {
          var newValue = customizer
            ? customizer(safeGet(object, key), srcValue, (key + ''), object, source, stack)
            : undefined;

          if (newValue === undefined) {
            newValue = srcValue;
          }
          assignMergeValue(object, key, newValue);
        }
      }, keysIn);
    }

    /**
     * A specialized version of `baseMerge` for arrays and objects which performs