.babelrc

{
  "presets": [
    [
      "env",
      {
        "targets": {
          "browsers": "> 1%",
          "uglify": true
        },
        "useBuiltIns": true
      }
    ],
    "react",
    "stage-2",
    "stage-3"
  ],
  "plugins": [
    "syntax-dynamic-import",
    [
      "transform-class-properties",
      {
        "spec": true
      }
    ],
    "transform-object-assign",
    [
      "module-alias",
      [
        {
          "src": "./app/javascript/packs",
          "expose": "packs"
        },
        { "src": "./app/assets/stylesheets", "expose": "stylesheets" },
        { "src": "./app/assets/images", "expose": "images" }
      ]
    ]
  ],
  "env": {
    "development": {
      "presets": ["react-hmre"]
    }
  }
}