code: function defaults (target, src) {
        each(src, function (prop) {
          if (typeof target[prop] === 'undefined') {
            target[prop] = src[prop];
          }
        });
      }
docs: /*!
  Copies each property from src onto target, but only if the property to
  copy to target is undefined.
  @param {Object} target Missing properties in this Object are filled in
  @param {Object} src