add all frontend files

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

@@ -0,0 +1,20 @@
+export default function contains(root, n) {
+  if (!root) {
+    return false;
+  }
+
+  // Use native if support
+  if (root.contains) {
+    return root.contains(n);
+  }
+
+  // `document.contains` not support with IE11
+  var node = n;
+  while (node) {
+    if (node === root) {
+      return true;
+    }
+    node = node.parentNode;
+  }
+  return false;
+}