Amazon recently announced the launch of support for Node.js 8.10 in AWS Lambda.

This brings the much anticipated ability to use asynchronous development patterns in serverless Lambda functions thanks to the support for Promises.

The ability to use the new handler types in AWS Lambda with async/await brings an escape from the so-called “callback hell” which frustrates many JavaScript developers. For more information on these new Lambda handler function types take a look at the documentation on AWS.

In order for those developing Netlify Functions to also enjoy the benefits of Node.js 8.10 we are now supporting this version of Node.js by default for all new serverless functions.

Pre-existing serverless functions will continue to use the previous runtime (Node.JS 6.10) until they are deployed again, at which time they will adopt the new default runtime of Node.js 8.10.

If you want to stick with an older version, you can change your default runtime with an environment variable. For example:

AWS_LAMBDA_JS_RUNTIME = nodejs6.10

You can find more details in the docs.