.babelrc

{
  "presets": [
    [
      "@babel/env",
      {
        "targets": {
          "node": "10.0"
        }
      }
    ]
  ],
  "plugins": [
    [
      "@babel/plugin-proposal-class-properties",
      {
        "loose": false
      }
    ],
    "@babel/plugin-proposal-export-default-from",
    "@babel/plugin-proposal-export-namespace-from",
    "babel-plugin-transform-export-extensions"
  ],
  "env": {
    "test": {
      "presets": [
        [
          "@babel/env",
          {
            "targets": {
              "node": "10.0"
            }
          }
        ]
      ],
      "plugins": [
        [
          "@babel/plugin-proposal-class-properties",
          {
            "loose": false
          }
        ],
        "@babel/plugin-proposal-export-default-from",
        "@babel/plugin-proposal-export-namespace-from",
        "babel-plugin-transform-export-extensions",
        [
          "istanbul",
          {
            "exclude": ["test/**/*"]
          }
        ]
      ]
    }
  }
}