The bundler generates a "rogue" "export default Fl();" if I import nostr-tools in entry point

Describe the bug

In src/service-worker.ts I have the sole line:

import { relayPool } from 'nostr-tools'

but the bundle (build/service-worker.js) contains:

export default Fl();

The same happens if I import nostr from 'nostr-tools' (or probably anything other nostr-tools.

My bundle is free of exports when importing Dexie from 'dexie' or a bunch of other imports.

I tried to figure out in the vite discord if this “transient” export might be a feature of sorts but I’m more and more convinced it is a bug in the bundler.

This bug was originally reported here.

Reproduction

https://github.com/Giszmo/tmpForBugReport is a blank svelteKit project with the added dependency nostr-tools and src/service-worker.ts` consisting of only an import from that dependency.

System Info

$ npx envinfo --system --npmPackages '{vite,@vitejs/*}' --binaries --browsers

  System:
    OS: Linux 5.10 Debian GNU/Linux 11 (bullseye) 11 (bullseye)
    CPU: (24) x64 AMD Ryzen 9 3900X 12-Core Processor
    Memory: 18.77 GB / 31.33 GB
    Container: Yes
    Shell: 5.1.4 - /bin/bash
  Binaries:
    Node: 18.6.0 - ~/.nvm/versions/node/v18.6.0/bin/node
    npm: 8.13.2 - ~/.nvm/versions/node/v18.6.0/bin/npm
  Browsers:
    Chromium: 103.0.5060.53
    Firefox: 96.0.3
  npmPackages:
    vite: ^3.0.0 => 3.0.4

Used Package Manager

npm

Logs

$ npm run build && npm run preview … (no errors)

Chromium dev console:

Uncaught SyntaxError: Unexpected token ‘export’ (at service-worker.js:6207:1)

Validations

• Follow our Code of Conduct
• Read the Contributing Guidelines.
• Read the docs.
• Check that there isn’t already an issue that reports the same bug to avoid creating a duplicate.
• Make sure this is a Vite issue and not a framework-specific issue. For example, if it’s a Vue SFC related bug, it should likely be reported to vuejs/core instead.
• Check that this is a concrete bug. For Q&A open a GitHub Discussion or join our Discord Chat Server.
• The provided reproduction is a minimal reproducible example of the bug.

[userquin]

@sapphi-red FYI:

What we do in pwa plugin is this: https://github.com/antfu/vite-plugin-pwa/blob/main/src/modules.ts#L108

On dev with plugin dev enabled, we need the type module when registering the sw and delegates sw build to Vite when using custom sw: https://github.com/antfu/vite-plugin-pwa/blob/main/src/plugins/dev.ts#L108

Otherwise we fallback to workbox-build.

I think the problem is that kit will never build the sw, current/latest and previous versions: talking with Ben, Rich always reject to include workbox-build and so ppl should use importScripts.

[userquin]

@sapphi-red you can also check my summary in kit issue