.babelrc

All Babel API options except the callbacks are allowed (because .babelrc files are serialized as JSON5).

Example:

{
  "plugins": ["transform-react-jsx"],
  "ignore": [
    "foo.js",
    "bar/**/*.js"
  ]
}

Use via package.json

You can alternatively choose to specify your .babelrc config from within package.json like so:

{
  "name": "my-package",
  "version": "1.0.0",
  "babel": {
    // my babel config here
  }
}

env option

You can use the env option to set specific options when in a certain environment:

{
  "env": {
    "production": {
      "plugins": ["transform-react-constant-elements"]
    }
  }
}

Options specific to a certain environment are merged into and overwrite non-env specific options.

The env key will be taken from process.env.BABEL_ENV, when this is not available then it uses process.env.NODE_ENV if even that is not available then it defaults to "development".

You can set this environment variable with the following:

Unix

At the start of a command:

BABEL_ENV=production YOUR_COMMAND_HERE

Or as a separate command:

export BABEL_ENV=production

YOUR_COMMAND_HERE

Windows

SET BABEL_ENV=production

YOUR_COMMAND_HERE

If you want your command to work across platforms, you can use cross-env

Lookup behavior

Babel will look for a .babelrc in the current directory of the file being transpiled. If one does not exist, it will travel up the directory tree until it finds either a .babelrc, or a package.json with a "babel": {} hash within.

Use "babelrc": false in options to stop lookup behavior, or provide the --no-babelrc CLI flag.