refactor: Simplify iterNodes implementation (#1689)

Moved filter logic into native TreeWalker implementation
for better performance and readability.

Removed support for open shadow root traversal.
Radios now resolve siblings within their rootNode scope
instead of the main document root.

Author: rkaraivanov

src/components/common/mixins/combo-box.ts

@@ -115,18 +115,20 @@ export abstract class IgcBaseComboBoxLikeComponent extends LitElement {
 }
 
 export function getItems<T extends HTMLElement>(root: Node, tagName: string) {
-  return iterNodes<T>(root, 'SHOW_ELEMENT', (item) => item.matches(tagName));
+  return iterNodes<T>(root, {
+    show: 'SHOW_ELEMENT',
+    filter: (item) => item.matches(tagName),
+  });
 }
 
 export function getActiveItems<T extends HTMLElement & { disabled: boolean }>(
   root: Node,
   tagName: string
 ) {
-  return iterNodes<T>(
-    root,
-    'SHOW_ELEMENT',
-    (item) => item.matches(tagName) && !item.disabled
-  );
+  return iterNodes<T>(root, {
+    show: 'SHOW_ELEMENT',
+    filter: (item) => item.matches(tagName) && !item.disabled,
+  });
 }
 
 export function getNextActiveItem<

src/components/common/util.ts

@@ -100,36 +100,40 @@ export function isDefined<T = unknown>(value: T) {
   return value !== undefined;
 }
 
-export function* iterNodes<T = Node>(
+export type IterNodesOptions<T = Node> = {
+  show?: keyof typeof NodeFilter;
+  filter?: (node: T) => boolean;
+};
+
+function createNodeFilter<T extends Node>(predicate: (node: T) => boolean) {
+  return {
+    acceptNode: (node: T): number =>
+      !predicate || predicate(node)
+        ? NodeFilter.FILTER_ACCEPT
+        : NodeFilter.FILTER_SKIP,
+  };
+}
+
+export function* iterNodes<T extends Node>(
   root: Node,
-  whatToShow?: keyof typeof NodeFilter,
-  filter?: (node: T) => boolean
+  options?: IterNodesOptions<T>
 ): Generator<T> {
   if (!isDefined(globalThis.document)) {
     return;
   }
 
-  const iter = globalThis.document.createTreeWalker(
-    root,
-    NodeFilter[whatToShow ?? 'SHOW_ALL']
-  );
-
-  let node = iter.nextNode() as T;
+  const whatToShow = options?.show
+    ? NodeFilter[options.show]
+    : NodeFilter.SHOW_ALL;
 
-  while (node) {
-    if (filter) {
-      if (filter(node)) {
-        yield node;
-      }
-    } else {
-      yield node;
-    }
+  const nodeFilter = options?.filter
+    ? createNodeFilter(options.filter)
+    : undefined;
 
-    if (isElement(node) && node.shadowRoot && node.shadowRoot.mode === 'open') {
-      yield* iterNodes(node.shadowRoot, whatToShow, filter);
-    }
+  const treeWalker = document.createTreeWalker(root, whatToShow, nodeFilter);
 
-    node = iter.nextNode() as T;
+  while (treeWalker.nextNode()) {
+    yield treeWalker.currentNode as T;
   }
 }
 

src/components/radio/utils.ts

@@ -1,4 +1,4 @@
-import { iterNodes } from '../common/util.js';
+import { type IterNodesOptions, getRoot, iterNodes } from '../common/util.js';
 import type IgcRadioComponent from './radio.js';
 
 type RadioQueryResult = {
@@ -36,13 +36,13 @@ export function getGroup(member: IgcRadioComponent) {
     return result;
   }
 
-  const iterator = iterNodes<IgcRadioComponent>(
-    globalThis.document.documentElement,
-    'SHOW_ELEMENT',
-    (radio) => radio.matches(member.tagName) && radio.name === member.name
-  );
+  const options: IterNodesOptions<IgcRadioComponent> = {
+    show: 'SHOW_ELEMENT',
+    filter: (radio) =>
+      radio.matches(member.tagName) && radio.name === member.name,
+  };
 
-  for (const each of iterator) {
+  for (const each of iterNodes<IgcRadioComponent>(getRoot(member), options)) {
     result.radios.push(each);
 
     if (!each.disabled) {