Function placeChild

docs/index.js:6294–6308

(newFiber, lastPlacedIndex, newIndex)

    return fiber;
  }
  function placeChild(newFiber, lastPlacedIndex, newIndex) {
    newFiber.index = newIndex;
    if (!shouldTrackSideEffects)
      return (newFiber.flags |= 1048576), lastPlacedIndex;
    newIndex = newFiber.alternate;
    if (null !== newIndex)
      return (
        (newIndex = newIndex.index),
        newIndex < lastPlacedIndex
          ? ((newFiber.flags |= 33554434), lastPlacedIndex)
          : newIndex
      );
    newFiber.flags |= 33554434;
    return lastPlacedIndex;
  }
  function placeSingleChild(newFiber) {
    shouldTrackSideEffects &&
      null === newFiber.alternate &&