Function updatePortalComponent

code/redux/public/app.js:10454–10477

(current, workInProgress, renderExpirationTime)

  }

  function updatePortalComponent(current, workInProgress, renderExpirationTime) {
    pushHostContainer(workInProgress, workInProgress.stateNode.containerInfo);
    var nextChildren = workInProgress.pendingProps;
    if (hasLegacyContextChanged()) {
      // Normally we can bail out on props equality but if context has changed
      // we don't do the bailout and we have to reuse existing props instead.
    } else if (workInProgress.memoizedProps === nextChildren) {
      return bailoutOnAlreadyFinishedWork(current, workInProgress);
    }

    if (current === null) {
      // Portals are special because we don't append the children during mount
      // but at commit. Therefore we need to track insertions which the normal
      // flow doesn't do during mount. This doesn't happen at the root because
      // the root always starts with a "current" with a null child.
      // TODO: Consider unifying this with how the root works.
      workInProgress.child = reconcileChildFibers(workInProgress, null, nextChildren, renderExpirationTime);
      memoizeProps(workInProgress, nextChildren);
    } else {
      reconcileChildren(current, workInProgress, nextChildren);
      memoizeProps(workInProgress, nextChildren);
    }
    return workInProgress.child;
  }

  function propagateContextChange(workInProgress, context, changedBits, renderExpirationTime) {
    var fiber = workInProgress.child;