.babelrc

{
  "presets": [
    [
      "@babel/preset-env",
      {
        "modules": false
      }
    ],
    "@babel/preset-react",
    "@babel/preset-flow"
  ],
  "plugins": [
    [
      "babel-plugin-styled-components",
      {
        "pure": true
      }
    ],
    [
      "@babel/plugin-proposal-decorators",
      {
        "legacy": true
      }
    ],
    "@babel/plugin-proposal-class-properties",
    "@babel/plugin-transform-flow-strip-types"
  ],
  "env": {
    "test": {
      "presets": ["@babel/preset-env", "@babel/preset-react", "@babel/preset-flow"],
      "plugins": [
        [
          "babel-plugin-styled-components",
          {
            "pure": true
          }
        ],
        [
          "@babel/plugin-proposal-decorators",
          {
            "legacy": true
          }
        ],
        "@babel/plugin-proposal-class-properties"
      ]
    },

    "commonjs": {
      "presets": [
        [
          "@babel/preset-env",
          {
            "useBuiltIns": false
          }
        ],
        "@babel/preset-react",
        "@babel/preset-flow"
      ],
      "plugins": [
        [
          "babel-plugin-styled-components",
          {
            "pure": true
          }
        ],
        [
          "@babel/plugin-proposal-decorators",
          {
            "legacy": true
          }
        ],
        "@babel/plugin-proposal-class-properties",
        "@babel/plugin-transform-flow-strip-types"
      ]
    },
    "es": {
      "presets": [
        [
          "@babel/preset-env",
          {
            "useBuiltIns": false,
            "modules": false
          }
        ],
        "@babel/preset-react",
        "@babel/preset-flow"
      ],
      "plugins": [
        [
          "babel-plugin-styled-components",
          {
            "pure": true
          }
        ],
        [
          "@babel/plugin-proposal-decorators",
          {
            "legacy": true
          }
        ],
        "@babel/plugin-proposal-class-properties",
        "@babel/plugin-transform-flow-strip-types"
      ]
    }
  }
}