Next.js on Vercel: SSR and local files

readme.md

Next.js and reading from a local JSON file with fs during build time:

	Local (dev)	Local (prod)	Vercel (prod)
getStaticProps	✅	✅	✅
getServerSideProps	✅	✅	❌

Using getServerSideProps and reading from a local JSON file with fs on Vercel causes "500: Internal Server Error" for unknown reasons. To fix this, the JSON file needs to be imported as a module.

users.ts

//import fs from 'fs';
import { default as users } from '../data/users.json';

export interface User {
	id: number;
	name: string;
}

export function getUsers(): User[] {
	//const users = JSON.parse(fs.readFileSync('data/users.json').toString());
	return users;
}