lib not supported for the html-encoding-sniffer

[nooperpudd]

issue

require() of ES Module /var/task/node_modules/@exodus/bytes/encoding-lite.js from /var/task/node_modules/html-encoding-sniffer/lib/html-encoding-sniffer.js not supported. Instead change the require of encoding-lite.js in /var/task/node_modules/html-encoding-sniffer/lib/html-encoding-sniffer.js to a dynamic import() which is available in all CommonJS modules.

[ChALkeR]

@nooperpudd Which Node.js version is this on?

[nooperpudd]

Node v22.20.0

[ChALkeR]

This should not be happening on 22.20
This is ERR_REQUIRE_ESM, which was deprecated in v20.19.0 / v22.12.0
Unless Node.js is run explicitly with --no-experimental-require-module, this should not be reachable

@nooperpudd How can I reproduce this / could you share a minimial setup how to observe this on 22.20?

[nooperpudd]

I just upgraded the node package nuxt-i18n-micro to v2.16.3. and the dependencies package version is jsdom (6.0.0)

[ChALkeR]

@nooperpudd Could you setup a repo to demonstrate this issue?
jsdom 6.0.0 should be unrelated and does not pull in @exodus/bytes anywhere in its dependency tree

[hvaughan3]

I see the same error but only when running on AWS Lambda using node 22 as well. This was working just fine with new builds from 2 weeks ago. Its only the build I ran on the 31st. Seems like something changed in a dependency between that time. I did not update any libraries in our project explicitly though I see jsdom went from 27.3.0 to 27.4.0 in that time so that is probably what did it.

*Edit: Forcing jsdom back down to 27.3.0 fixed it for this error. Ended up having to overriding parse5 down to v7 also for something similar.

[ChALkeR]

@hvaughan3

1. What is the exact Node.js version this is happening on?
2. Do you have a way to reproduce this that you could share? (ideally a repo or a gist)

[frodeaa]

It happens with node@24 when loaded as transitive dependency via jsdom

=> Found "jsdom@27.4.0"
=> Found "@exodus/bytes@1.6.0"
info Reasons this module exists
   - "jsdom" depends on it
   - Hoisted from "jsdom#@exodus#bytes"
   - Hoisted from "jsdom#html-encoding-sniffer#@exodus#bytes"
info Disk size without dependencies: "432KB"
info Disk size with unique dependencies: "432KB"
info Disk size with transitive dependencies: "432KB"
info Number of shared dependencies: 0

Error [ERR_REQUIRE_ESM]: require() of ES Module /var/task/node_modules/@exodus/bytes/encoding-lite.js from /var/task/node_modules/html-encoding-sniffer/lib/html-encoding-sniffer.js not supported.
Instead change the require of encoding-lite.js in /var/task/node_modules/html-encoding-sniffer/lib/html-encoding-sniffer.js to a dynamic import() which is available in all CommonJS modules.
    at TracingChannel.traceSync (node:diagnostics_channel:328:14)
    at Object.<anonymous> (/var/task/node_modules/html-encoding-sniffer/lib/html-encoding-sniffer.js:2:41)

[ChALkeR]

@frodeaa once again: could you share a repo or gist to reproduce this?

ERR_REQUIRE_ESM is deprecated since Node.js >=22.12.0 | ^20.19.0, for all Node.js versions that jsdom or @exodus/bytes supports (as specified in engines), and should not be triggered outside of special conditions (like purposely enabling it via a Node.js flag).

Node.js documentation link: https://nodejs.org/docs/latest/api/errors.html#err_require_esm

If this can be reproduced outside of those conditions on supported Node.js versions, this needs a specific reproducible example of conditions in which this happens.

[frodeaa]

@ChALkeR Reproduced with https://github.com/frodeaa/exodus-html-encoding-sniffe

node --version
v24.12.0

npm install && npm run build
node -e "const m = require('./dist/handler.js'); m.handler()"

Unable to reproduce it directly with node, only when loaded via AWS Lambda container,
so it is not clear what can be done to "fix" this

[ChALkeR]

Thanks!
This being AWS Lamdba specific explains things, they indeed purposely disabled Node.js default behavior for ESM loading.

See https://docs.aws.amazon.com/lambda/latest/dg/lambda-nodejs.html#nodejs-experimental-features on how to restore it.
It's the default behavior in RC status.

Moreover, @exodus/bytes doesn't use require(ESM) itself, it's just ESM-only.
You can't require() it if you have synchronous ESM loader disabled.

---

Upd: as of 2026-02-20, it's marked as Stable

[ChALkeR]

See also jsdom/jsdom@ebad33c, discussion in jsdom/jsdom#3961, jsdom/jsdom#3959
jsdom already relies on require(esm) to work.

[ChALkeR]

See also discussion at Vercel and their docs

Also, this thread

[hvaughan3]

Ah that makes sense. Appreciate the help! I will give that a try Monday. Apologies for not getting back to you on it earlier.