Function cloneElement

lib/assets/react-source/development/react.js:1209–1279

* Clone and return a new ReactElement using element as the starting point. * See https://reactjs.org/docs/react-api.html#cloneelement

(element, config, children)

	 */

	function cloneElement(element, config, children) {
	  if (!!(element === null || element === undefined)) {
	    {
	      throw Error( "React.cloneElement(...): The argument must be a React element, but you passed " + element + "." );
	    }
	  }

	  var propName; // Original props are copied

	  var props = _assign({}, element.props); // Reserved names are extracted


	  var key = element.key;
	  var ref = element.ref; // Self is preserved since the owner is preserved.

	  var self = element._self; // Source is preserved since cloneElement is unlikely to be targeted by a
	  // transpiler, and the original source is probably a better indicator of the
	  // true owner.

	  var source = element._source; // Owner will be preserved, unless ref is overridden

	  var owner = element._owner;

	  if (config != null) {
	    if (hasValidRef(config)) {
	      // Silently steal the ref from the parent.
	      ref = config.ref;
	      owner = ReactCurrentOwner.current;
	    }

	    if (hasValidKey(config)) {
	      key = '' + config.key;
	    } // Remaining properties override existing props


	    var defaultProps;

	    if (element.type && element.type.defaultProps) {
	      defaultProps = element.type.defaultProps;
	    }

	    for (propName in config) {
	      if (hasOwnProperty.call(config, propName) && !RESERVED_PROPS.hasOwnProperty(propName)) {
	        if (config[propName] === undefined && defaultProps !== undefined) {
	          // Resolve default props
	          props[propName] = defaultProps[propName];
	        } else {
	          props[propName] = config[propName];
	        }
	      }
	    }
	  } // Children can be more than one argument, and those are transferred onto
	  // the newly allocated props object.


	  var childrenLength = arguments.length - 2;

	  if (childrenLength === 1) {