Babel plugin that rewrites Promise references to es6-promise, but only if necessary. Tested with Node.js 0.10 and above.

$ npm install --save-dev babel-plugin-es6-promise

Then add es6-promise to your Babel config, like:

{
  "plugins": ["es6-promise"]
}

es6-promise must be installed separately.

This plugin rewrites files that reference the Promise built-in. It inserts the following code at the top of each file:

var _Promise = typeof Promise === 'undefined'
  ? require('es6-promise').Promise
  : Promise

This means es6-promise is only loaded when there is no Promise built-in available. Each Promise reference is rewritten to _Promise.

Note that require() is used rather than a ES2015 module import. This may make it difficult to do further import transforms.

Also note that the _Promise variable name in this example is determined by Babel and may differ depending on your code.