Edge Runtime Incompatibility

[LilaRest]

Hello @ljharb!
First, thanks for all the hard work on your libraries.

Our NextJS builds are failing with the following error since our last dependencies upgrade:

Dynamic Code Evaluation (e. g. 'eval', 'new Function', 'WebAssembly.compile') not allowed in Edge Runtime 
Learn More: https://nextjs.org/docs/messages/edge-dynamic-code-evaluation
The error was caused by importing 'traverse/index.js' in 'REDACTED'

After hours of investigation, it led us to this repository and is-generator-function. Those two are using Function('return async function () {}')(); which is considered dynamic code by the compiler.

We are not using these two libraries directly, but instead use traverse which indirectly relies on those two libraries. And it's likely that in the most recent version of traverse (or of one of its dependencies), is-async-function and is-generator-function have been introduced as dependencies, so breaking our builds.

Is there an easy way for you to remove these "dynamic code" parts to unlock edge runtime support? Or should we explore other solutions?

[ljharb]

(linking to inspect-js/is-generator-function#44)

[ljharb]

I've published async-function and refactored this package to use it, so now this package has no more Function usage - and async-function uses multiple entry points, only the "legacy" of which uses Function. The hope is that your bundler should automatically pick up the pure syntax version, and everything will Just Work without any configuration changes.

[LilaRest]

Hey @ljharb! I just tested the fix and it did it!
Will you be pushing a similar fix for inspect-js/is-generator-function#44 ?
Thanks!

[ljharb]

Awesome! Yep, I'm planning to do that as well, and I'll also update a number of other deeply-depended-on packages to use them too.

[LilaRest]

@ljharb Fantastic! Thanks again!