google-api-nodejs-client is Google's officially supported node.js client library for accessing Google APIs, it also supports authorization and authentication with OAuth 2.0.
This client comes with an OAuth2 client that allows you to retrieve an access token and refreshes the token and re-try the request seamlessly if token is expired. The basics of Google's OAuth 2.0 implementation is explained on Google Authorization and Authentication documentation.
Note: This library is currently in alpha status.
The project's home page can be found on GitHub