Function updateFragment

code/new-context-api/public/app.js:8418–8430

(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, expirationTime);
      existing['return'] = returnFiber;
      return existing;
    }
  }

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