.babelrc.json for React development.

.babelrc.json

{
  "presets": [
    [
      "@babel/preset-env",
      {
        "useBuiltIns": "usage"
      }
    ],
    "@babel/preset-react",
    "@babel/preset-flow"
  ],
  "plugins": [
    "@babel/plugin-syntax-jsx",
    "transform-flow-strip-types",
    "transform-class-properties"
  ]
}