Function addDepsToRegistry

packages/core/src/defer/utils.ts:122–135

(currentDeps: T | null, newDeps: T)

 * making sure that a dependency doesn't yet exist in the registry.
 */
export function addDepsToRegistry<T extends DependencyDef[]>(currentDeps: T | null, newDeps: T): T {
  if (!currentDeps || currentDeps.length === 0) {
    return newDeps;
  }

  const currentDepSet = new Set(currentDeps);
  for (const dep of newDeps) {
    currentDepSet.add(dep);
  }

  // If `currentDeps` is the same length, there were no new deps and can
  // return the original array.
  return currentDeps.length === currentDepSet.size ? currentDeps : (Array.from(currentDepSet) as T);
}

/** Retrieves a TNode that represents main content of a defer block. */
export function getPrimaryBlockTNode(tView: TView, tDetails: TDeferBlockDetails): TContainerNode {