using nodemailer in nextjs can't resolve child_process

[steveswork]

Using nodemailer in one of the pages/api routes produces the following error message:
[ error ] ./node_modules/nodemailer/lib/sendmail-transport/index.js Module not found: Can't resolve 'child_process' in 'C:\ua-demo\node_modules\nodemailer\lib\sendmail-transport'

With my understanding being that the next.js pages/api routes run in the server environment alone, it is a wonder that this error is occurring. How could this be addressed so that I can send email updates to my users?

An example has been added here at codesandbox.io. I think that we need to build a copy of the program directly on a local machine to reproduce.

Also discussed on SO

[Timer]

Please provide a fully reproducing example so someone may provide assistance.

[steveswork]

I will not be able to provide it. NDA aside, the code example will be voluminous to post. If it helps though, the Nodemailer package is used in a module which is a domain service that sends out update alerts to users. The pages/api uses this domain service.

The issue then is that when I run npm run dev, I get the error above. By the way, my package.json contains this snippet: { "scripts": { "dev": "clear && next dev", ... }, ... }

[steveswork]

@Timer, just wondering if you've had time to take another look at this issue? I cannot build this app without resolving this issue first. Is there another npm emailer package better suited for NextJs applications that I can use instead?

[Timer]

Like I said previously:

Please provide a fully reproducing example so someone may provide assistance.

Without this, we're unable to provide assistance.

[steveswork]

Ok, I've updated my original post with a codesandbox link to an example.

[nicholaschiang]

Hey @Timer shouldn't Next.js automatically load server-side only modules in the pages/api directory? Why is this even an error?

[kmturley]

I had a similar issue. It seems that a generic package import, traverses all files underneath regardless of whether the methods are actually called:

import { clientSideMethod } from 'mypackage'

Actually first goes to the root index.js inside the package and calls:

export * from './file'; // contains server-side code
export * from './utils'; // contains client-side code only

Therefore the error was triggered. Solutions are:

1. Use a more specific import import { clientSideMethod } from '../../node_modules/mypackage/dist/utils'
2. Dynamically import server-side modules when needed
3. Split packages or modules into client-side vs server-side