redux-devtools/packages/redux-devtools-slider-monitor/examples/todomvc/.babelrc

{
  "presets": [
    "@babel/preset-env",
    "@babel/preset-react",
    "@babel/preset-typescript"
  ],
  "plugins": [
    "@babel/plugin-proposal-class-properties",
    "react-hot-loader/babel"
  ]
}