function shallowClearAndCopy(src, dst) {
  dst = dst || {};

  angular.forEach(dst, function(value, key) {
    delete dst[key];
  });

  for (var key in src) {
    if (src.hasOwnProperty(key) && !(key.charAt(0) === '$' && key.charAt(1) === '$')) {
      dst[key] = src[key];
    }
  }

  return dst;
}
Create a shallow copy of an object and clear other fields from the destination