Sveltekit + Windows = ERR_REQUIRE_ESM

Using this library with SvelteKit 1.0.0-next.115 on Windows gives the following error:

Error [ERR_REQUIRE_ESM]: Must use import to load ES Module: C:\quick-i18n-throwaway-demo-main\node_modules\svelte-intl-precompile\index.js
require() of ES modules is not supported.
require() of C:\quick-i18n-throwaway-demo-main\node_modules\svelte-intl-precompile\index.js from C:\quick-i18n-throwaway-demo-main\node_modules\vite\dist\node\chunks\dep-bc228bbb.js is an ES module file as it is a .js file whose nearest parent package.json contains "type": "module" which defines all .js files in that package scope as ES modules.
Instead rename index.js to end in .cjs, change the requiring code to use import(), or remove "type": "module" from C:\quick-i18n-throwaway-demo-main\node_modules\svelte-intl-precompile\package.json.

    at Object.Module._extensions..js (internal/modules/cjs/loader.js:1080:13)
    at Module.load (internal/modules/cjs/loader.js:928:32)
    at Function.Module._load (internal/modules/cjs/loader.js:769:14)
    at Module.require (internal/modules/cjs/loader.js:952:19)
    at require (internal/modules/cjs/helpers.js:88:18)
    at nodeRequire (C:\quick-i18n-throwaway-demo-main\node_modules\vite\dist\node\chunks\dep-bc228bbb.js:68707:17)
    at ssrImport (C:\quick-i18n-throwaway-demo-main\node_modules\vite\dist\node\chunks\dep-bc228bbb.js:68660:20)
    at eval (C:\quick-i18n-throwaway-demo-main\src\routes\index.svelte:7:31)
    at instantiateModule (C:\quick-i18n-throwaway-demo-main\node_modules\vite\dist\node\chunks\dep-bc228bbb.js:68693:166)

You can see the error on a Windows machine and using your repo: https://github.com/cibernox/quick-i18n-throwaway-demo - but oddly the error isn’t thrown on a remote Gitpod environment which is Linux I’m assuming - and you must be devving on a Mac is why you never came across this error? I’m so confused why Windows would spin this up as it seems yet another classic ESM-Vite challenging bug.

[tobiaskohlbau]

I would like to add some information I gathered. I’m not sure if my issue is directly related to this, but the error is quiet similar.

I’ve a setup with rollup and included svelte-intl-precompile in order to compile the translations beforehand. The issue on my specific use case was that during SSR svelte-intl-precompile gets loaded in esm mode, initialized by "type": "module" in the projects package.json. By the looks of it svelte-intl-precompile or to better name it precompile-intl-runtime is not able to run in esm mode without an external bundler.

There are two missing parts:

• There exists no main entrypoint in the package.json of precompile-intl-runtime.
• precompile-intln-runtime is not a valid es module as it does not have file endings in it’s compiled module imports.

The second point is derived from the nodejs documentation which states:

Relative specifiers like ‘./startup.js’ or ‘…/config.mjs’. They refer to a path relative to the location of the importing file. The file extension is always necessary for these.

The typescript compiler does not issue such output and therefore does not produce valid es modules. See microsoft/TypeScript/issues/42151 and microsoft/TypeScript/pull/42184. The recommended way is to ad the js extension already in the typescript files. Which is IMHO kind of confusing, but it works.

Maybe the svelte/vite/node handling on windows is minimal different on windows than on other OS and therefore produces this issues (only a wild guess). Could be that addressing the invalid esm module issues solves this issue as a side effect.

I’ve created a fork and applied the needed fixes, it’s over here for reference.

[ydoc118]

@cibernox I’ve gotten it to work by using the full path to import
import { init, getLocaleFromNavigator, addMessages } from '../../node_modules/svelte-intl-precompile';

whereas import { init, getLocaleFromNavigator, addMessages } from 'svelte-intl-precompile'; throws the same error @vish01 is getting