Function findHydrationRoot

packages/core/src/hydration/i18n.ts:431–449

()

    assertDefined(tI18n, 'Expected i18n data to be present in a given TView slot during hydration');

  function findHydrationRoot() {
    if (isRootTemplateMessage(subTemplateIndex)) {
      // This is the root of an i18n block. In this case, our hydration root will
      // depend on where our parent TNode (i.e. the block with i18n applied) is
      // in the DOM.
      ngDevMode && assertDefined(parentTNode, 'Expected parent TNode while hydrating i18n root');
      const rootNode = locateNextRNode(hydrationInfo!, tView, lView, parentTNode!) as Node;

      // If this i18n block is attached to an <ng-container>, then we want to begin
      // hydrating directly with the RNode. Otherwise, for a TNode with a physical DOM
      // element, we want to recurse into the first child and begin there.
      return parentTNode!.type & TNodeType.ElementContainer ? rootNode : rootNode.firstChild;
    }

    // This is a nested template in an i18n block. In this case, the entire view
    // is translated, and part of a dehydrated view in a container. This means that
    // we can simply begin hydration with the first dehydrated child.
    return hydrationInfo?.firstChild as Node;
  }

  const currentNode = findHydrationRoot();
  ngDevMode && assertDefined(currentNode, 'Expected root i18n node during hydration');