build(babel): clean up babel warnings

Author: bnmajor

.babelrc

@@ -14,6 +14,8 @@
   "plugins": [
     "@babel/plugin-transform-runtime",
     ["@babel/plugin-proposal-decorators", { "legacy": true }],
-    ["@babel/plugin-proposal-class-properties", { "loose": true }]
+    ["@babel/plugin-proposal-class-properties", { "loose": true }],
+    ["@babel/plugin-proposal-private-methods", { "loose": true }],
+    ["@babel/plugin-proposal-private-property-in-object", { "loose": true }]
   ]
 }