Exception for Multer to release v2 with ESM

[bjohansebas]

Hi, I would like to request an exception for the ESM/CommonJS ADR (#323) to release Multer version 2, since one of its dependencies is ESM (https://www.npmjs.com/package/file-type), which makes this module unable to be CommonJS.

The other option is to fork file-type and convert it to CommonJS, but do we really want that? Or look for an alternative to that package, or move the support of v2 to Node >= 22.12 (which would go against the LTS plan).

Ref:

• Plans for v2? multer#1042 (comment)
• It is used, behind (https://www.npmjs.com/package/stream-file-type), which depends on the new version (https://github.com/expressjs/multer/blob/d983eb219979ec41936fd29d9db24e51fad9d0f3/package.json#L30)

cc: @expressjs/express-tc @expressjs/multer-collaborators @UlisesGascon @LinusU

[ljharb]

why not just use a pre-ESM major? That's what most of the ecosystem does with ESM-only packages.

[ctcpip]

must be outdated comments because we don't use that dependency so this is a non-issue

[ctcpip]

also, please note that multer v2 is going to be a security release using the v1 API due to breaking changes. the new API, which was slated for v2, is going to need to go into v3 (or later)

[bjohansebas]

@ctcpip It is used, behind (https://www.npmjs.com/package/stream-file-type), which depends on the new version (https://github.com/expressjs/multer/blob/d983eb219979ec41936fd29d9db24e51fad9d0f3/package.json#L30)

[ctcpip]

ah, ok