Function updateFragment

lib/assets/react-source/development/react.js:17295–17307

(returnFiber, current, fragment, expirationTime, key)

	  }

	  function updateFragment(returnFiber, current, fragment, expirationTime, key) {
	    if (current === null || current.tag !== Fragment) {
	      // Insert
	      var created = createFiberFromFragment(fragment, returnFiber.mode, expirationTime, key);
	      created.return = returnFiber;
	      return created;
	    } else {
	      // Update
	      var existing = useFiber(current, fragment);
	      existing.return = returnFiber;
	      return existing;
	    }
	  }

	  function createChild(returnFiber, newChild, expirationTime) {
	    if (typeof newChild === 'string' || typeof newChild === 'number') {