add all frontend files

node_modules/rc-table/es/utils/offsetUtil.js

@@ -0,0 +1,14 @@
+import { getDOM } from "rc-util/es/Dom/findDOMNode";
+
+// Copy from `rc-util/Dom/css.js`
+export function getOffset(node) {
+  var element = getDOM(node);
+  var box = element.getBoundingClientRect();
+  var docElem = document.documentElement;
+
+  // < ie8 not support win.pageXOffset, use docElem.scrollLeft instead
+  return {
+    left: box.left + (window.pageXOffset || docElem.scrollLeft) - (docElem.clientLeft || document.body.clientLeft || 0),
+    top: box.top + (window.pageYOffset || docElem.scrollTop) - (docElem.clientTop || document.body.clientTop || 0)
+  };
+}