Function conditionallyAnnotateNodePath

packages/core/src/hydration/annotate.ts:758–791

* Serializes node location in cases when it's needed, specifically: * * 1. If `tNode.projectionNext` is different from `tNode.next` - it means that * the next `tNode` after projection is different from the one in the original * template. Since hydration relies on `tNode.next`, this seri

(
  ngh: SerializedView,
  tNode: TNode,
  lView: LView<unknown>,
  excludedParentNodes: Set<number> | null,
)

 *     connection to identify the location of a node.
 */
function conditionallyAnnotateNodePath(
  ngh: SerializedView,
  tNode: TNode,
  lView: LView<unknown>,
  excludedParentNodes: Set<number> | null,
) {
  if (isProjectionTNode(tNode)) {
    // Do not annotate projection nodes (<ng-content />), since
    // they don't have a corresponding DOM node representing them.
    return;
  }

  // Handle case #1 described above.
  if (
    tNode.projectionNext &&
    tNode.projectionNext !== tNode.next &&
    !isInSkipHydrationBlock(tNode.projectionNext)
  ) {
    appendSerializedNodePath(ngh, tNode.projectionNext, lView, excludedParentNodes);
  }

  // Handle case #2 described above.
  // Note: we only do that for the first node (i.e. when `tNode.prev === null`),
  // the rest of the nodes would rely on the current node location, so no extra
  // annotation is needed.
  if (
    tNode.prev === null &&
    tNode.parent !== null &&
    isDisconnectedNode(tNode.parent, lView) &&
    !isDisconnectedNode(tNode, lView)
  ) {
    appendSerializedNodePath(ngh, tNode, lView, excludedParentNodes);
  }
}

/**
 * Determines whether a component instance that is represented