TS import errors in Vercel Serverless Functions

[shut tartan]

Why do I see this in the Vercel Serverless Functions logs if everything works fine for me locally when I run `vercel --dev' but somehow it doesn't work on the Vercel server

Error [ERR_REQUIRE_ESM]: require() of ES Module /var/task/node_modules/@octokit/core/dist-src/index.js from /var/task/utils/github.js not supported.
Instead change the require of index.js in /var/task/utils/github.js to a dynamic import() which is available in all CommonJS modules.
    at /opt/rust/nodejs.js:2:12062
    at Function.or (/opt/rust/nodejs.js:2:12436)
    at e.<computed>.me._load (/opt/rust/nodejs.js:2:12032)
    at TracingChannel.traceSync (node:diagnostics_channel:315:14)
    at s (/opt/rust/bytecode.js:2:1094) {
  code: 'ERR_REQUIRE_ESM'
}
Node.js process exited with exit status: 1. The logs above can help with debugging the issue.

If you need more details - tell me

[heady island]

Hi @shut tartan. I'm kapa.ai, your friendly support bot. I will try to answer your question by searching through the knowledge base. :wave:

---

This error is related to importing ESM (ECMAScript Modules) in a CommonJS environment. Based on the information provided in the knowledge sources, I can explain why this issue occurs and suggest some potential solutions.

The error you're seeing is likely due to the difference between your local development environment and the Vercel serverless environment. Here are a few reasons why this might be happening:

1. Module Resolution: As mentioned in Why does my Serverless Function work locally but not when deployed?, there can be differences in how modules are resolved between local and serverless environments.

2. ESM vs CommonJS: The error suggests that you're trying to use require() to import an ES Module. This is not supported in Node.js when working with ESM.

3. Package Compatibility: Some packages might be ESM-only, which can cause issues in a CommonJS environment.

To resolve this issue, you can try the following:

1. Use dynamic import: As the error message suggests, you can change the require() statement to a dynamic import(). This is available in all CommonJS modules.

2. Check package compatibility: Ensure that the packages you're using (like @octokit/core) are compatible with the Node.js version and module system used by Vercel's serverless functions.

3. Use serverComponentsExternalPackages: If you're using Next.js, you might want to add the problematic package to the serverComponentsExternalPackages configuration in your next.config.js. However, note that this might not work with next dev --turbo as mentioned in this issue.

4. Verify environment variables: As mentioned in Why does my Serverless Function work locally but not when deployed?, ensure that all necessary environment variables are correctly set in your Vercel deployment.

5. Check for case-sensitivity: As noted in How do I resolve a 'module not found' error?, Vercel deployments use a case-sensitive filesystem, which might cause issues if there are letter-casing inconsistencies in your imports.

If the issue persists after trying these solutions, you might want to check your Vercel logs for more detailed information or consider reaching out to Vercel support for further assistance.

Note: you can ask me a follow up question by @ mentioning me again :speech_balloon:

@shut tartan Kapa.ai is still learning and improving, please let me know how I did by reacting below.

[shut tartan]

https://www.npmjs.com/package/@octokit/core#:~:text=As we use conditional exports%2C you will need to adapt your tsconfig.json. See the TypeScript docs on package.json "exports".

@heady island https://www.npmjs.com/package/@octokit/core#:~:text=As we use conditional exports%2C you will need to adapt your tsconfig.json. See the TypeScript docs on package.json "exports".

[heady island]

Let me check the knowledge base for you again. Give me one moment! :books:

---

Thank you for providing that link. It appears you're referring to the @octokit/core package and its usage of conditional exports. This is indeed relevant to the issue you were experiencing with Vercel Serverless Functions. Let me explain how this relates to your situation and what you can do about it.

The @octokit/core package uses conditional exports, which can cause issues with TypeScript and module resolution, especially in environments like Vercel's serverless functions. To address this, you need to make some adjustments to your tsconfig.json file. Here's what you should do:

1. Update your tsconfig.json:
   As mentioned in the TypeScript documentation on package.json exports, you need to add the following to your tsconfig.json:

   {
     "compilerOptions": {
       "moduleResolution": "node16",
       "target": "es2022"
     }
   }
   

   This configuration tells TypeScript to use the Node.js 16+ module resolution strategy, which is compatible with packages using conditional exports.

2. Use ESM imports:
   Instead of using require(), use ESM import syntax in your code. For example:

   import { Octokit } from '@octokit/core'
   

3. Ensure your package.json is set up for ESM:
   Add "type": "module" to your package.json file to indicate that your project uses ESM.

4. Update Vercel configuration:
   Make sure your Vercel project is set to use a Node.js version that supports ESM and conditional exports (Node.js 16 or later).

By making these changes, you should be able to resolve the module import issues you were experiencing with @octokit/core in your Vercel Serverless Functions.

Remember, these changes might affect how other parts of your application work, so test thoroughly after making these modifications. If you encounter any new issues, you may need to adjust other parts of your codebase or configuration to be compatible with ESM.

Note: you can ask me a follow up question by @ mentioning me again :speech_balloon: