function baseCopy(source, object, props) {
	      if (!props) {
	        props = object;
	        object = {};
	      }
	      var index = -1,
	          length = props.length;

	      while (++index < length) {
	        var key = props[index];
	        object[key] = source[key];
	      }
	      return object;
	    }
Copies the properties of `source` to `object`.

@private
@param {Object} source The object to copy properties from.
@param {Object} [object={}] The object to copy properties to.
@param {Array} props The property names to copy.
@returns {Object} Returns `object`.