Function removeStaleDehydratedBranch

packages/core/src/hydration/views.ts:147–178

* In the case that we have control flow that changes branches between server and * client, we're left with dehydrated content that will not be used. We need to find * it and clean it up at the right time so that we don't see duplicate content for * a few moments before the application reaches sta

(hostLView: LView, tNode: TNode)

 * dehydrated content for the branch that is now stale from the server and removes it.
 */
function removeStaleDehydratedBranch(hostLView: LView, tNode: TNode): void {
  let currentTNode: TNode | null = tNode;
  while (currentTNode) {
    // We can return here if we've found the dehydrated view and cleaned it up.
    // Otherwise we continue on until we either find it or reach the start of
    // the control flow.
    if (cleanupMatchingDehydratedViews(hostLView, currentTNode)) return;

    if ((currentTNode.flags & TNodeFlags.isControlFlowStart) === TNodeFlags.isControlFlowStart) {
      // we've hit the top of the control flow loop
      break;
    }

    currentTNode = currentTNode.prev;
  }

  currentTNode = tNode.next; // jump to place we started so we can navigate down from there

  while (currentTNode) {
    if ((currentTNode.flags & TNodeFlags.isInControlFlow) !== TNodeFlags.isInControlFlow) {
      // we've exited control flow and need to exit the loop.
      break;
    }

    // Similar to above, we can return here if we've found the dehydrated view
    // and cleaned it up. Otherwise we continue on until we either find it or
    // reach the end of the control flow.
    if (cleanupMatchingDehydratedViews(hostLView, currentTNode)) return;

    currentTNode = currentTNode.next;
  }
}

function hasMatchingDehydratedView(lContainer: LContainer, template: string | null): boolean {
  const views = lContainer[DEHYDRATED_VIEWS];