Add initial versions

dom-query.js

@@ -0,0 +1,29 @@
+/**
+@license
+Copyright (c) 2022 trading_peter
+This program is available under Apache License Version 2.0
+*/
+
+/**
+ * Helps to automatically query elements in the shadow dom of the extended element.
+ */
+export const DomQuery = function(superClass) {
+  return class extends superClass {
+
+    constructor() {
+      super();
+
+      const handler = {
+        get: (o, selector) => {
+          const root = this.shadowRoot || this;
+          const el = selector[0] === '?' ? root.querySelector(selector.substring(1)) : root.querySelector(`#${selector}`);
+          if (el !== null) {
+            return el;
+          }
+        }
+      };
+
+      this.$ = new Proxy({}, handler);
+    }
+  };
+}