Function updateFragment

docs/index.js:6378–6393

(returnFiber, current, fragment, lanes, key)

    return current;
  }
  function updateFragment(returnFiber, current, fragment, lanes, key) {
    if (null === current || 7 !== current.tag)
      return (
        (current = createFiberFromFragment(
          fragment,
          returnFiber.mode,
          lanes,
          key
        )),
        (current.return = returnFiber),
        current
      );
    current = useFiber(current, fragment);
    current.return = returnFiber;
    return current;
  }
  function createChild(returnFiber, newChild, lanes) {
    if (
      ("string" === typeof newChild && "" !== newChild) ||