add all frontend files

node_modules/rc-util/es/Dom/shadow.js

@@ -0,0 +1,18 @@
+function getRoot(ele) {
+  var _ele$getRootNode;
+  return ele === null || ele === void 0 || (_ele$getRootNode = ele.getRootNode) === null || _ele$getRootNode === void 0 ? void 0 : _ele$getRootNode.call(ele);
+}
+
+/**
+ * Check if is in shadowRoot
+ */
+export function inShadow(ele) {
+  return getRoot(ele) instanceof ShadowRoot;
+}
+
+/**
+ * Return shadowRoot if possible
+ */
+export function getShadowRoot(ele) {
+  return inShadow(ele) ? getRoot(ele) : null;
+}