Export extend methods

.changeset/unlucky-swans-smash.md

@@ -0,0 +1,5 @@
+---
+'@chialab/quantum': patch
+---
+
+Export extend methods.

src/extend.js

@@ -2,21 +2,14 @@ import { extendElement } from './Element.js';
 import { extendNode } from './Node.js';
 import { extendTreeWalker } from './TreeWalker.js';
 
-/**
- * Whether the DOM environment is extended.
- */
-let extended = false;
-
 /**
  * Extend constructors in the given window namespace.
  * @param {Window & typeof globalThis} window The window namespace to extend.
  */
 export function extend(window) {
-    if (extended) {
-        return;
-    }
     extendNode(window.Node);
     extendElement(window.Element);
-    extendTreeWalker(window.TreeWalker, window.NodeFilter);
-    extended = true;
+    if (typeof window.TreeWalker !== 'undefined') {
+        extendTreeWalker(window.TreeWalker, window.NodeFilter);
+    }
 }

src/index.js

@@ -1,6 +1,9 @@
 import { extend } from './extend.js';
 
 export { extend };
+export { extendNode } from './Node.js';
+export { extendElement } from './Element.js';
+export { extendTreeWalker } from './TreeWalker.js';
 export { Realm, attachRealm, getRealm } from './Realm.js';
 
 if (typeof window !== 'undefined') {