Exported function arguments getting mapped as exports, breaking build

[craigrileyuk]

Describe the bug

I've recently started getting an error with the arguments inside exported functions that are being marked as exports.

So if I have export function useReactiveMedia(source, callback) then useReactiveMedia, source and callback all get marked as exports for that file and will break my build if they're used anywhere else (thus generating an import for them).

So in the repo linked below, you will receive a:

Uncaught SyntaxError: The requested module 'http://localhost:5174/src/composables/useCan.js' doesn't provide an export named: 'options'

error because the useTest.js file gets this prepended in its output:

import { options } from "/src/composables/useCan.js";

UPDATE

Traced the issue back to unjs/unimport version 5.7.0+. Suggest you lock to 5.6.0 until they fix it.

Reproduction

https://github.com/craigrileyuk/auto-import-jsdoc-issue

System Info

System:
    OS: macOS 13.7.8
    CPU: (8) x64 Intel(R) Core(TM) i7-6700K CPU @ 4.00GHz
    Memory: 82.22 MB / 32.00 GB
    Shell: 5.9 - /bin/zsh
  Binaries:
    Node: 25.5.0 - ~/.nvm/versions/node/v25.5.0/bin/node
    npm: 11.8.0 - ~/.nvm/versions/node/v25.5.0/bin/npm
    pnpm: 10.28.2 - ~/Library/pnpm/pnpm
  Browsers:
    Chrome: 145.0.7632.117
    Firefox: 148.0
    Safari: 18.6

Used Package Manager

npm

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[ilyaliao]

It seems like a bug in mlly. See unjs/mlly#336

You can install mlly@1.8.1 to temporarily avoid this issue.

I think the next dependency upgrade should fix it. /cc @antfu

[chenyuncai]

happend to me too. I have a function define 'export const aFunc = (data: string) => {}'

it generate 'aFuync' and 'data' from this file

I changed the param definition to aFunc = (...params: any[]) => {}, it avoid too.

[SimonEast]

It's my first time attempting to use unplugin-auto-import with a Vite/Vue repo, and it's completely failing with fatal JS syntax errors in my browser console. I'm pretty sure it's due to this bug, as auto-imports.d.ts has weird entries where it's trying to import the name of function parameters as well as the functions themselves.

One of the modules triggering the issue is a pretty vanilla structure like this:

export default function x() {...}
export function y(a, b) {...}

For some reason unplugin-auto-import is trying to "import" a and b.

I tried running npm i mlly@1.8.1 and restarting Vite, but it made no difference.

Also tried npm i unimport@5.6.x and restarting Vite, but it didn't help either.

How are people working around this bug (other than modifying the modules in question, which is not ideal)?

[SimonEast]

Update: I ended up updating all 15+ of my npm packages to their latest versions, including Vite, restarted Vite again (fixed some SCSS deprecation warnings) and then it started to work without the import issues. 🎉 My auto-imports.d.ts file looks cleaner now.

I'm pretty sure I was already using the latest unplugin-auto-import (only just installed it an hour ago), but maybe some other package was creating a conflict. No idea which one at this stage, but hopefully this helps someone else out there.