babel.config.json

{
  "presets": ["@babel/preset-env", "@babel/preset-react", "@babel/preset-flow"],
  "plugins": [
    "@babel/plugin-transform-runtime",
    "@babel/plugin-syntax-dynamic-import",
    "@babel/plugin-transform-modules-commonjs",
    "@babel/plugin-proposal-class-properties"
  ],
  "env": {
    "development": {
      "plugins": ["transform-es2015-modules-commonjs"]
    },
    "test": {
      "plugins": [
        "transform-es2015-modules-commonjs",
        "@babel/plugin-proposal-class-properties"
      ],
      "presets": ["@babel/preset-react"]
    }
  }
}