document async functions

Author: swyxio

Diff for: README.md

@@ -182,7 +182,12 @@ If you need an escape hatch and are building your lambda in some way that is inc
 
 ## Debugging
 
-To debug lambdas, prepend the `serve` command with [npm's package runner npx](https://medium.com/@maybekatz/introducing-npx-an-npm-package-runner-55f7d4bd282b) `npx --node-arg=--inspect netlify-lambda serve ...`. Additionally, (1) make sure that sourcemaps are built along the way (e.g. in the webpack configuration and the `tsconfig.json` if typescript is used) and (2) webpack's uglification is turned off with `optimization: { minimize: false }`. If using VSCode,  it is likely that the `sourceMapPathOverrides` have to be adapted for breakpoints to work.
+To debug lambdas, prepend the `serve` command with [npm's package runner npx](https://medium.com/@maybekatz/introducing-npx-an-npm-package-runner-55f7d4bd282b) `npx --node-arg=--inspect netlify-lambda serve ...`. Additionally:
+
+1. make sure that sourcemaps are built along the way (e.g. in the webpack configuration and the `tsconfig.json` if typescript is used) 
+2. webpack's uglification is turned off with `optimization: { minimize: false }`. If using VSCode,  it is likely that the `sourceMapPathOverrides` have to be adapted for breakpoints to work.
+
+Netlify Functions [run in Node v8.10](https://www.netlify.com/blog/2018/04/03/node.js-8.10-now-available-in-netlify-functions/) and you may need to run the same version to mirror the environment locally. Also make sure to check that you aren't [committing one of these common Node 8 mistakes in Lambda!](https://serverless.com/blog/common-node8-mistakes-in-lambda/)
 
 Don't forget to search our issues in case someone has run into a similar problem you have!