.babelrc

{
  "presets": ["next/babel", "es2015", "react", "stage-3"],
  "env": {
    "development": {
      "plugins": [
        "transform-object-assign",
        "transform-object-rest-spread",
        "transform-object-set-prototype-of-to-assign",
        ["transform-class-properties", { "spec": true }],
        "react-hot-loader/babel",
        "styled-jsx/babel"
      ],
    },
    "test": {
      "plugins": [
        "transform-es2015-modules-commonjs",
        "transform-object-set-prototype-of-to-assign",
        ["transform-class-properties", { "spec": true }],
        "styled-jsx/babel"
      ]
    },
    "production": {
      "plugins": [
        "transform-object-assign",
        "transform-object-rest-spread",
        "transform-object-set-prototype-of-to-assign",
        ["transform-class-properties", { "spec": true }],
        "styled-jsx/babel"
      ]
    }
  }
}