wip(task-timeline): stage changes

app/babel.config.js

@@ -1,3 +1,8 @@
 module.exports = {
   presets: ["@vue/cli-plugin-babel/preset"],
+  plugins: [
+    ["@babel/plugin-proposal-private-methods", { loose: true }],
+    ["@babel/plugin-proposal-class-properties", { loose: true }],
+    ["@babel/plugin-proposal-private-property-in-object", { loose: true }],
+  ],
 };