.babelrc

{
  "presets": ["@babel/preset-env", "@babel/preset-react"],
  "env": {
      "production": {
          "plugins": ["@babel/plugin-proposal-object-rest-spread", "styled-jsx/babel", [
            "@babel/plugin-proposal-class-properties",
            {
              "loose": true
            }
          ]]
      },
      "development": {
          "plugins": ["@babel/plugin-proposal-object-rest-spread", "styled-jsx/babel", [
            "@babel/plugin-proposal-class-properties",
            {
              "loose": true
            }
          ]]
      },
      "test": {
          "plugins": ["@babel/plugin-proposal-object-rest-spread", "styled-jsx/babel-test", [
            "@babel/plugin-proposal-class-properties",
            {
              "loose": true
            }
          ]]
      }
  }
}