.babelrc

{
  "presets": [
    [
      "env",
      {
        "modules": false,
        "targets": {
          "browsers": [
            "> 1%",
            "last 2 versions",
            "not ie <= 8"
          ]
        }
      }
    ]
  ],
  "plugins": [
    "babel-plugin-dynamic-import-node"
  ],
  "env": {
    "build": {
      "plugins": [
        ["transform-object-rest-spread", { "useBuiltIns": true }]
      ]
    },
    "test": {
      "plugins": [
        "transform-es2015-modules-commonjs",
        "babel-plugin-dynamic-import-node",
        "transform-object-rest-spread"
      ],
      "presets": [
        [
          "env",
          {
            "targets": {
              "node": "current"
            }
          }
        ]
      ]
    },
    "styleguide": {
      "plugins": [
        "transform-es2015-modules-commonjs",
        ["@babel/plugin-proposal-object-rest-spread", { "useBuiltIns": true }]
      ],
      "presets": [
        [
          "env",
          {
            "modules": false,
            "targets": {
              "browsers": [
                "> 1%",
                "last 2 versions",
                "not ie <= 8"
              ]
            }
          }
        ]
      ]
    }
  }
}