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Removing wasm2js (asm.js) support #635

Description

@sbc100

We are proposing to remove wasm2js support upstream in emscripten: emscripten-core/emscripten#27608

Would remove that asm.js targets from sql-js be possible at this point?

(emscripten already does not support browsers that pre-date wasm support).

Activity

  1. lovasoa commented on Oct 9, 2026

    @lovasoa
    Member

    Looking at GitHub release asset download statistics, I think there is still some real use for asm.js

    Across the five latest releases, asm.js assets received 3,116 downloads, versus 6,599 for Wasm assets.

    jsdelivr also shows some usage: https://data.jsdelivr.com/v1/stats/packages/npm/sql.js@1.8.0/files?period=2026-09&limit=100

    I think the setup journey and compatibility of wasm still isn't great after all these years. There is still no standard way to handle wasm files across bundlers to my knowledge...

  2. sbc100 commented on Oct 9, 2026

    @sbc100
    ContributorAuthor

    If you are worried about bundling or serving multiple files, perhaps you can just use -sSINGLE_FILE to embed the Wasm code into the JavaScript (avoiding the second file).

    If you think there are users out there who cannot switch to WebAssembly, perhaps you could post on emscripten-core/emscripten#27608, and perhaps we could try to find one or two concrete examples, so we can help understand what is holding them back.

  3. lovasoa commented on Oct 9, 2026

    @lovasoa
    Member

    Could we have a grace period when we deprecate it, show a warning, and let user come back to us if needed?

  4. sbc100 commented on Oct 9, 2026

    @sbc100
    ContributorAuthor

    Yes, of course. We added the deprecation warning already back in emscripten-core/emscripten#27655. That was released 3 weeks ago in 6.0.10.

  5. sbc100 commented on Oct 9, 2026

    @sbc100
    ContributorAuthor

    We can certainly wait a few more weeks or months if needed.

  6. lovasoa commented on Oct 9, 2026

    @lovasoa
    Member

    thanks! I'll open a pr on our side to deprecate asm.js, introduce inline wasm, and update our docs ci, etc

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