Require Hook

How to use the require hook.

One of the ways you can use Babel is through the require hook. The require hook will bind itself to node’s require and automatically compile files on the fly. This is equivalent to CoffeeScript’s coffee-script/register.

Install

$ npm install babel-register

Usage

require("babel-register");

All subsequent files required by node with the extensions .es6, .es, .jsx and .js will be transformed by Babel.

Polyfill not included

You must include the polyfill separately when using features that require it, like generators.

NOTE: By default all requires to node_modules will be ignored. You can override this by passing an ignore regex via:

require("babel-register")({
  // This will override `node_modules` ignoring - you can alternatively pass
  // an array of strings to be explicitly matched or a regex / glob
  ignore: false
});

Specifying options

require("babel-register")({
  // Optional ignore regex - if any filenames **do** match this regex then they
  // aren't compiled.
  ignore: /regex/,

  // Ignore can also be specified as a function.
  ignore: function(filename) {
    if (filename === '/path/to/es6-file.js') {
      return false;
    } else {
      return true;
    }
  },

  // Optional only regex - if any filenames **don't** match this regex then they
  // aren't compiled
  only: /my_es6_folder/,

  // Setting this will remove the currently hooked extensions of .es6, `.es`, `.jsx`
  // and .js so you'll have to add them back if you want them to be used again.
  extensions: [".es6", ".es", ".jsx", ".js"]
});

You can pass in all other options as well, including plugins and presets. But note that the closest .babelrc to each file still applies, and takes precedence over any options you pass in here.

Environment variables

By default babel-node and babel-register will save to a json cache in your temporary directory.

This will heavily improve with the startup and compilation of your files. There are however scenarios where you want to change this behaviour and there are environment variables exposed to allow you to do this.

BABEL_CACHE_PATH

Specify a different cache location.

$ BABEL_CACHE_PATH=/foo/my-cache.json babel-node script.js

BABEL_DISABLE_CACHE

Disable the cache.

$ BABEL_DISABLE_CACHE=1 babel-node script.js