Function getFirstNativeNode

packages/core/src/render3/node_manipulation.ts:699–751

(lView: LView, tNode: TNode | null)

 * Native nodes are returned in the order in which those appear in the native tree (DOM).
 */
export function getFirstNativeNode(lView: LView, tNode: TNode | null): RNode | null {
  if (tNode !== null) {
    ngDevMode &&
      assertTNodeType(
        tNode,
        TNodeType.AnyRNode |
          TNodeType.AnyContainer |
          TNodeType.Icu |
          TNodeType.Projection |
          TNodeType.LetDeclaration,
      );

    const tNodeType = tNode.type;
    if (tNodeType & TNodeType.AnyRNode) {
      return getNativeByTNode(tNode, lView);
    } else if (tNodeType & TNodeType.Container) {
      return getBeforeNodeForView(-1, lView[tNode.index]);
    } else if (tNodeType & TNodeType.ElementContainer) {
      const elIcuContainerChild = tNode.child;
      if (elIcuContainerChild !== null) {
        return getFirstNativeNode(lView, elIcuContainerChild);
      } else {
        const rNodeOrLContainer = lView[tNode.index];
        if (isLContainer(rNodeOrLContainer)) {
          return getBeforeNodeForView(-1, rNodeOrLContainer);
        } else {
          return unwrapRNode(rNodeOrLContainer);
        }
      }
    } else if (tNodeType & TNodeType.LetDeclaration) {
      return getFirstNativeNode(lView, tNode.next);
    } else if (tNodeType & TNodeType.Icu) {
      let nextRNode = icuContainerIterate(tNode as TIcuContainerNode, lView);
      let rNode: RNode | null = nextRNode();
      // If the ICU container has no nodes, than we use the ICU anchor as the node.
      return rNode || unwrapRNode(lView[tNode.index]);
    } else {
      const projectionNodes = getProjectionNodes(lView, tNode);
      if (projectionNodes !== null) {
        if (Array.isArray(projectionNodes)) {
          return projectionNodes[0];
        }
        const parentView = getLViewParent(lView[DECLARATION_COMPONENT_VIEW]);
        ngDevMode && assertParentView(parentView);
        return getFirstNativeNode(parentView!, projectionNodes);
      } else {
        return getFirstNativeNode(lView, tNode.next);
      }
    }
  }

  return null;
}

export function getProjectionNodes(lView: LView, tNode: TNode | null): TNode | RNode[] | null {
  if (tNode !== null) {