Function getClosestRElement

packages/core/src/render3/node_manipulation.ts:502–548

(
  tView: TView,
  tNode: TNode | null,
  lView: LView,
)

 * @returns `null` if the `RElement` can't be determined at this time (no parent / projection)
 */
export function getClosestRElement(
  tView: TView,
  tNode: TNode | null,
  lView: LView,
): RElement | null {
  let parentTNode: TNode | null = tNode;
  // Skip over element and ICU containers as those are represented by a comment node and
  // can't be used as a render parent. Also skip let declarations since they don't have a
  // corresponding DOM node at all.
  while (
    parentTNode !== null &&
    parentTNode.type & (TNodeType.ElementContainer | TNodeType.Icu | TNodeType.LetDeclaration)
  ) {
    tNode = parentTNode;
    parentTNode = tNode.parent;
  }

  // If the parent tNode is null, then we are inserting across views: either into an embedded view
  // or a component view.
  if (parentTNode === null) {
    // We are inserting a root element of the component view into the component host element and
    // it should always be eager.
    return lView[HOST];
  } else {
    ngDevMode && assertTNodeType(parentTNode, TNodeType.AnyRNode | TNodeType.Container);
    if (isComponentHost(parentTNode)) {
      ngDevMode && assertTNodeForLView(parentTNode, lView);
      const {encapsulation} = tView.data[
        parentTNode.directiveStart + parentTNode.componentOffset
      ] as ComponentDef<unknown>;
      // We've got a parent which is an element in the current view. We just need to verify if the
      // parent element is not a component. Component's content nodes are not inserted immediately
      // because they will be projected, and so doing insert at this point would be wasteful.
      // Since the projection would then move it to its final destination. Note that we can't
      // make this assumption when using the Shadow DOM, because the native projection placeholders
      // (<content> or <slot>) have to be in place as elements are being inserted.
      if (
        encapsulation === ViewEncapsulation.None ||
        encapsulation === ViewEncapsulation.Emulated
      ) {
        return null;
      }
    }

    return getNativeByTNode(parentTNode, lView) as RElement;
  }
}

/**
 * Find a node in front of which `currentTNode` should be inserted.