Function reconcileChildren

docs/external/js/react-dom.development.js:16891–16906

(current, workInProgress, nextChildren, renderExpirationTime)

  }

  function reconcileChildren(current, workInProgress, nextChildren, renderExpirationTime) {
    if (current === null) {
      // If this is a fresh new component that hasn't been rendered yet, we
      // won't update its child set by applying minimal side-effects. Instead,
      // we will add them all to the child before it gets rendered. That means
      // we can optimize this reconciliation pass by not tracking side-effects.
      workInProgress.child = mountChildFibers(workInProgress, null, nextChildren, renderExpirationTime);
    } else {
      // If the current child is the same as the work in progress, it means that
      // we haven't yet started any work on these children. Therefore, we use
      // the clone algorithm to create a copy of all the current children.
      // If we had any progressed work already, that is invalid at this point so
      // let's throw it out.
      workInProgress.child = reconcileChildFibers(workInProgress, current.child, nextChildren, renderExpirationTime);
    }
  }

  function forceUnmountCurrentAndReconcile(current, workInProgress, nextChildren, renderExpirationTime) {
    // This function is fork of reconcileChildren. It's used in cases where we