.babelrc

{
  "presets": [
    ["latest", { "es2015": { "modules": false } }],
    "stage-2"
  ],
  "env": {
    "coverage": {
      "plugins": [
        ["istanbul", {
          "exclude": [
            "spec/javascripts/**/*"
          ]
        }],
        ["transform-define", {
          "process.env.BABEL_ENV": "coverage"
        }]
      ]
    }
  }
}