NextJS@12 and .mjs in node_modules

[qpre]

Hello,

I just ran a few tests on an app I have running on tf-next 0.11.2.

the app uses urql (which uses a lib called wonka)

when deploying using next@11 everything works fine but when I deploy with next@12 all I get from the NEXT_PAGE_LAMBDA_0 logs is ERROR Error [ERR_MODULE_NOT_FOUND]: Cannot find module '/var/task/node_modules/wonka/dist/wonka.mjs' imported from /var/task/node_modules/@urql/core/dist/urql-core.mjs

When I explore the lambda's deployment package I can see that indeed wonka.mjs does not exist but a wonka.js exists.

I tried doing the same deploy to Vercel and it works fine, therefore I think something (maybe the node version ?) is not on par but I can't seem to find what and how to fix it.

any idea ?

[ofhouse]

Yeah, Next.js 12 has support for esm while our module currently hasn't.
Since Vercel also uses Lambda (And the same Node.js version under the hood as this module) the problem is probably located in the the layer we use between Next.js and Lambda, which currently doesn't support esm.

You could probably workaround this by adding the following setting to your next.config.js:

module.exports = {
  experimental: {
    esmExternals: false
  }
}

[qpre]

that solves it yes, thanks !