.babelrc

{
  "presets": [
    [
      "@babel/preset-env",
      {
        "targets": "node 12.0"
      }
    ]
  ],
  "plugins": [
    "@babel/plugin-transform-flow-strip-types",
    [
      "@babel/plugin-transform-block-scoping",
      {
        "throwIfClosureRequired": true
      }
    ]
  ]
}