[BUG] ExperimentalWarning: Support for loading ES Module in require() is an experimental feature and might change at any time #7857

alexsch01 · 2024-10-18T16:51:28Z

Is there an existing issue for this?

I have searched the existing issues

This issue exists in the latest npm version

I am using the latest npm

Current Behavior

When installing any package with Node.js v23.0.0 and npm v10.9.0, I get the following warning

(node:10424) ExperimentalWarning: Support for loading ES Module in require() is an experimental feature and might change at any time
(Use `node --trace-warnings ...` to show where the warning was created)

Expected Behavior

No response

Steps To Reproduce

No response

Environment

npm: 10.9.0
Node.js: 23.0.0
OS Name: Windows 10 22H2
npm config: default

; node bin location = C:\Program Files\nodejs\node.exe
; node version = v23.0.0
; npm local prefix = C:\Users\$USER\Downloads\test
; npm version = 10.9.0
; cwd = C:\Users\$USER\Downloads\test
; HOME = C:\Users\$USER
; Run `npm config ls -l` to show all defaults.

The text was updated successfully, but these errors were encountered:

shadowspawn · 2024-10-18T22:29:24Z

This is triggered by the experimental --experimental-require-module flag being made the default behaviour in Node.js 23. Related links:

MikeMcC399 · 2024-10-19T12:56:32Z

It's not necessary to install anything with npm to provoke the ExperimentalWarning.

For example, even with no npm modules installed, executing npm view npm version results in the ExperimentalWarning:

$ npm view npm version
(node:5212) ExperimentalWarning: Support for loading ES Module in require() is an experimental feature and might change at any time
(Use `node --trace-warnings ...` to show where the warning was created)
10.9.0

Ubuntu 24.04.1 LTS
Node.js v23.0.0
npm 10.9.0 (latest)

Same ExperimentalWarning for many other CLI commands from https://docs.npmjs.com/cli/v10/commands:

npm audit
npm ci
npm doctor
npm init
npm install
npm install-ci-test
npm ls
npm outdated
npm prune
npm repo
npm show
... etc

MikeMcC399 · 2024-10-19T13:08:20Z

See also discussion in Can we supress the new experimental warning from the new default require(esm) setting? nodejs/node#55417

MikeMcC399 · 2024-10-19T14:51:29Z

Setting the environment variable NODE_OPTIONS='--trace-warnings' produces some trace output.

$ NODE_OPTIONS='--trace-warnings' npm view npm view
(node:6610) ExperimentalWarning: Support for loading ES Module in require() is an experimental feature and might change at any time
    at emitExperimentalWarning (node:internal/util:273:11)
    at loadESMFromCJS (node:internal/modules/cjs/loader:1388:5)
    at Module._compile (node:internal/modules/cjs/loader:1525:5)
    at Object..js (node:internal/modules/cjs/loader:1680:16)
    at Module.load (node:internal/modules/cjs/loader:1328:32)
    at Function._load (node:internal/modules/cjs/loader:1138:12)
    at TracingChannel.traceSync (node:diagnostics_channel:315:14)
    at wrapModuleLoad (node:internal/modules/cjs/loader:218:24)
    at Module.require (node:internal/modules/cjs/loader:1350:12)
    at require (node:internal/modules/helpers:138:16)

RedYetiDev · 2024-10-19T15:30:35Z

FYI the ESM being require()d is supports-color.

MikeMcC399 · 2024-10-19T16:27:50Z

@RedYetiDev

FYI the ESM being require()d is supports-color.

You're right!

cli/package.json

Line 113 in 780afc5

"supports-color": "^9.4.0",

where [email protected] and above is pure ESM

As identified by @ljharb in debug causes npm to always issue an experimental ESM warning in node 23 debug-js/debug#975 and relayed above by @shadowspawn , debug is using the following code to check on the availability of supports-color.

const supportsColor = require('supports-color');

where debug is effectively allowing an ESM version of supports-color to be installed and used:

  "peerDependenciesMeta": {
    "supports-color": {
      "optional": true
    }

So I guess the underlying issue debug-js/debug#975 needs to be resolved by debug.

MikeMcC399 · 2024-10-19T17:52:52Z

To test, I downgraded to [email protected] prior to PR fix: better color support detection #6556 in [email protected]

npm install [email protected] -g

and there was no more warning under Node.js v23.0.0 from

npm view npm version

Why?: Because the following error will happen when running server. ```bash $ npm run dev > [email protected] dev > vite VITE v5.4.9 ready in 310 ms ➜ Local: http://localhost:5173/ ➜ Network: use --host to expose ➜ press h + enter to show help (node:59826) ExperimentalWarning: Support for loading ES Module in require() is an experimental feature and might change at any time (Use `node --trace-warnings ...` to show where the warning was created) file:///home/toor/repos/github.com/rnazmo/my-web-tools/tailwind.config.js:56 plugins: [require("tailwindcss-animate")], ^ ReferenceError: require is not defined at file:///home/toor/repos/github.com/rnazmo/my-web-tools/tailwind.config.js:56:12 at ModuleJobSync.runSync (node:internal/modules/esm/module_job:367:35) at ModuleLoader.importSyncForRequire (node:internal/modules/esm/loader:325:47) at loadESMFromCJS (node:internal/modules/cjs/loader:1392:24) at Module._compile (node:internal/modules/cjs/loader:1525:5) at Object..js (node:internal/modules/cjs/loader:1680:16) at Module.load (node:internal/modules/cjs/loader:1328:32) at Function._load (node:internal/modules/cjs/loader:1138:12) at TracingChannel.traceSync (node:diagnostics_channel:315:14) at wrapModuleLoad (node:internal/modules/cjs/loader:218:24) at Module.require (node:internal/modules/cjs/loader:1350:12) at require (node:internal/modules/helpers:138:16) at /home/toor/repos/github.com/rnazmo/my-web-tools/node_modules/tailwindcss/lib/lib/load-config.js:54:27 at loadConfig (/home/toor/repos/github.com/rnazmo/my-web-tools/node_modules/tailwindcss/lib/lib/load-config.js:58:6) at getTailwindConfig (/home/toor/repos/github.com/rnazmo/my-web-tools/node_modules/tailwindcss/lib/lib/setupTrackingContext.js:71:116) at /home/toor/repos/github.com/rnazmo/my-web-tools/node_modules/tailwindcss/lib/lib/setupTrackingContext.js:100:92 at /home/toor/repos/github.com/rnazmo/my-web-tools/node_modules/tailwindcss/lib/processTailwindFeatures.js:46:11 at plugins (/home/toor/repos/github.com/rnazmo/my-web-tools/node_modules/tailwindcss/lib/plugin.js:38:69) at LazyResult.runOnRoot (/home/toor/repos/github.com/rnazmo/my-web-tools/node_modules/postcss/lib/lazy-result.js:329:16) at LazyResult.runAsync (/home/toor/repos/github.com/rnazmo/my-web-tools/node_modules/postcss/lib/lazy-result.js:258:26) at LazyResult.async (/home/toor/repos/github.com/rnazmo/my-web-tools/node_modules/postcss/lib/lazy-result.js:160:30) at LazyResult.then (/home/toor/repos/github.com/rnazmo/my-web-tools/node_modules/postcss/lib/lazy-result.js:404:17) Node.js v23.0.0 ``` What I did: ```bash $ mise use node@22 ✔mise ~/repos/github.com/rnazmo/my-web-tools/.mise.toml tools: [email protected] $ node --version v22.9.0 ``` Ref: npm/cli#7857 https://mise.jdx.dev/cli/use.html See also: https://tailwindcss.com/docs/configuration

What I did: ```bash $ mise --version 2024.10.7 linux-x64 (7d15bd5 2024-10-14) $ mise ls-remote node | tail -n 5 22.7.0 22.8.0 22.9.0 22.10.0 23.0.0 $ mise use node@22 mise ~/repos/github.com/rnazmo/vite-react-ts-tailwind-template/.mise.toml tools: [email protected] $ node --version v22.9.0 ```` NOTE: Use 22 not 23 because 23 is still new and will cause trouble. Ref: https://mise.jdx.dev/demo.html https://mise.jdx.dev/lang/node.html https://mise.jdx.dev/cli/ls-remote.html https://mise.jdx.dev/cli/use.html npm/cli#7857

MikeMcC399 · 2024-10-25T06:24:54Z

Under Node.js v23.1.0 the warning provides additional debugging information which confirms the previous analysis:

$ npm view npm version
(node:13088) ExperimentalWarning: CommonJS module /home/mike/n/lib/node_modules/npm/node_modules/debug/src/node.js is loading ES Module /home/mike/n/lib/node_modules/npm/node_modules/supports-color/index.js using require().
Support for loading ES Module in require() is an experimental feature and might change at any time
(Use `node --trace-warnings ...` to show where the warning was created)
10.9.0

Message enhancement through module: include module information in require(esm) warning nodejs/node#55397

deleonjulio · 2024-10-29T00:48:04Z

Out of nowhere, npm install and npm start doesnt work in my project. I have to downgrade my node version to make it work.

MikeMcC399 · 2024-10-29T09:20:13Z

@deleonjulio

Out of nowhere, npm install and npm start doesnt work in my project. I have to downgrade my node version to make it work.

That sounds like a different issue. This issue is about an ExperimentalWarning only, where npm continues to work.

SparK-Cruz · 2024-10-29T22:13:37Z

What can we do other than rewrite everything between npm to debug, inclusive, in ESM?

ljharb · 2024-10-30T04:44:39Z

@SparK-Cruz you can't do anything, whatsoever. Only node, npm, or debug, can do something about it.

SparK-Cruz · 2024-10-30T12:24:45Z

@SparK-Cruz you can't do anything, whatsoever. Only node, npm, or debug, can do something about it.

@ljharb We can always open a pull request... if gets approved or not is another story. Worst case scenario I can fork it and add it to the AUR.

ljharb · 2024-10-30T14:30:33Z

@SparK-Cruz yes, a PR to debug would be a possible path forward.

Forking things to AUR without the consent of the maintainer doesn’t actually help the ecosystem, though, and it makes things worse for AUR users because they’re not really using the actual software.

npm/cli#7857

mantoni · 2024-10-31T09:45:12Z

Hm, I think the cause of this is npm cli directly depending on a different major version of supports-color than chalk and debug. I tried downgrading to v7.x in #7887 and it fixes the problem and seems to work fine.

wellwelwel · 2024-11-04T07:53:05Z

I opened a PR with a really simple approach to fix it from supports-color side, by adding an automation to also export the index.js (ESM) to index.cjs. This allows the supports-color to support both CommonJS, ES Modules and browsers, fixing the issue in both debug and npm/cli, and allowing Node.js to keep the experimental warning.

Also, no changes would be necessary either on the debug or npm/cli side (except maybe forcing an update to the new supports-color version, if approved).

feat: support for CommonJS chalk/supports-color#156

EDIT: Unfortunately, supports-color's decision is in fact not to be compatible with CommonJS.

damisparks · 2024-11-04T12:15:56Z

I get this error on npm publish:

(node:85003) ExperimentalWarning: Support for loading ES Module in require() is an experimental feature and might change at any time
(Use `node --trace-warnings ...` to show where the warning was created)
npm error code ENOENT
npm error syscall open

I was only able to publish by using node 22.

ljharb · 2024-11-04T15:08:57Z

@damisparks node v23.0.0 is broken, so you'd need to be on v23.1.0. The experimental warning would still occur, though.

damisparks · 2024-11-04T15:31:02Z

@ljharb After upgrading to v23.1.0 , I could publish.
I still see the experimental warning, as you said.

(node:19390) ExperimentalWarning: CommonJS module /Users/damisparks/.nvm/versions/node/v23.1.0/lib/node_modules/npm/node_modules/debug/src/node.js is loading ES Module /Users/damisparks/.nvm/versions/node/v23.1.0/lib/node_modules/npm/node_modules/supports-color/index.js using require().
Support for loading ES Module in require() is an experimental feature and might change at any time
(Use `node --trace-warnings ...` to show where the warning was created)

jonkoops · 2024-11-06T17:27:55Z

Considering the CLI targets Node.js versions that all support ESM, perhaps the easiest way to mitigate this issue is to start using ES modules instead of CommonJS? Is there any particular blocker that might prevent doing so?

ljharb · 2024-11-06T18:25:22Z

@jonkoops the issue occurs in debug, which is CJS, so npm using ESM would have no effect on it whatsoever.

jonkoops · 2024-11-06T18:41:36Z

@ljharb I see you already logged debug-js/debug#975 for that, thanks I'll follow the discussion there. Still, this would presumably also affect the CLI even if this debug itself was ESM, but just move the warning up the chain.

So my question still stands, would there be any technical reason the CLI itself could not be authored in ESM in terms of compatibility?

ljharb · 2024-11-06T18:55:31Z

Probably not? but there'd also be no concrete benefit, either - only a subjectively ideological one.

planetarquasar · 2024-11-08T11:30:25Z

Any update on this about the fix? Cannot build the Laradock because of this bug. During the build stuck on this progress:

 => => # Support for loading ES Module in require() is an experimental feature and might change at any time
 => => # (Use `node --trace-warnings ...` to show where the warning was created)
 => => # (node:3567) ExperimentalWarning: CommonJS module /home/laradock/.nvm/versions/node/v23.1.0/lib/node_modules/npm/node_modules/debug/src/node.js is loading ES Module /home/laradock/.nvm/versions/node/v23.1.0/lib/node_modules/npm/n  => => # ode_modules/supports-color/index.js using require().
 => => # Support for loading ES Module in require() is an experimental feature and might change at any time
 => => # (Use `node --trace-warnings ...` to show where the warning was created)

ljharb · 2024-11-08T11:32:40Z

@planetarquasar those are just log messages, it shouldn't interfere with a build process. you can set NODE_OPTIONS='--disable-warning=ExperimentalWarning', though, and suppress them.

planetarquasar · 2024-11-08T11:36:13Z

Where should I put this?

ljharb · 2024-11-08T11:42:01Z

in your environment - it's an environment variable. Happy to help with further questions, but let's please not continue pinging people by commenting on this issue :-)

(npm folks, feel free to hide some of these tangents as off topic)

gba-foundever · 2024-11-17T16:02:45Z

For information, this 'WARNING' was make my yoeman installation not working with issue: yeoman/yeoman#1778

putting
export NODE_OPTIONS='--disable-warning=ExperimentalWarning' in bash removed the WARNING and the issue

orome · 2024-11-18T14:49:42Z

For information, this 'WARNING' was make my yoeman installation not working with issue: yeoman/yeoman#1778

putting export NODE_OPTIONS='--disable-warning=ExperimentalWarning' in bash removed the WARNING and the issue

So is this what we should all be doing? Any reason not to?

shivanraptor · 2024-11-19T01:51:46Z

Where should I put this?

Example:

NODE_OPTIONS='--disable-warning=ExperimentalWarning' npm i

wraithgar · 2024-11-26T20:24:27Z

~~This was fixed in the latest versions of both npm 9 and 10~~

Debug was updated but this didn't resolve the issue. See later comments in this issue.

songyang-dev · 2024-11-26T23:14:08Z

This is still happening to me. I'll make a new issue

shivanraptor · 2024-11-27T03:10:28Z

This is still happening to me. I'll make a new issue

Confirmed. I use npm version 10.9.0, this issue still appears.

Environment:

macOS 15.1.1
npm 10.9.0
node v23.3.0
vite 5.4.11
react 18.3.1

package.json

{
  "name": "my-project-name",
  "private": true,
  "version": "0.0.0",
  "type": "module",
  "scripts": {
    "dev": "vite",
    "build": "tsc -b && vite build",
    "lint": "eslint .",
    "preview": "vite preview"
  },
  "dependencies": {
    "@chatui/core": "^2.4.2",
    "react": "^18.3.1",
    "react-dom": "^18.3.1"
  },
  "devDependencies": {
    "@eslint/js": "^9.13.0",
    "@types/react": "^18.3.12",
    "@types/react-dom": "^18.3.1",
    "@vitejs/plugin-react-swc": "^3.5.0",
    "eslint": "^9.13.0",
    "eslint-plugin-react-hooks": "^5.0.0",
    "eslint-plugin-react-refresh": "^0.4.14",
    "globals": "^15.11.0",
    "typescript": "~5.6.2",
    "typescript-eslint": "^8.11.0",
    "vite": "^5.4.10"
  }
}

wraithgar · 2024-11-27T04:32:08Z

debug was updated in npm, but didn't fix the issue. This is not something npm can fix. This is an issue with node and/or debug. Please follow debug-js/debug#975 for more info.

This should not be a problem in node 22 anymore (ref: debug-js/debug#975 (comment)).

ljharb · 2024-11-27T04:58:00Z

(it's something npm can work around, by pinning to an older version of supports-color, but it's best resolved in node itself)

alexsch01 added Bug thing that needs fixing Needs Triage needs review for next steps labels Oct 18, 2024

doni108108doni mentioned this issue Oct 19, 2024

[BUG] <title> #7860

Closed

2 tasks

MikeMcC399 mentioned this issue Oct 19, 2024

Can we supress the new experimental warning from the new default require(esm) setting? nodejs/node#55417

Open

MikeMcC399 mentioned this issue Oct 21, 2024

tests(deps): add node.js 23 (current) to tests cypress-io/github-action#1281

Merged

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zloirock added a commit to zloirock/core-js that referenced this issue Oct 30, 2024

disable NodeJS ExperimentalWarning on npm install

dfc45d9

npm/cli#7857

alexsch01 closed this as completed Oct 31, 2024

alexsch01 reopened this Oct 31, 2024

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wellwelwel mentioned this issue Nov 4, 2024

debug causes npm to always issue an experimental ESM warning in node 23 debug-js/debug#975

Open

gba-foundever mentioned this issue Nov 17, 2024

Got "Current environment doesn't provides some necessary feature this generator needs" when trying generators yeoman/yeoman#1778

Open

targos mentioned this issue Nov 19, 2024

[v22.x] backport unflagging of --experimental-require-module and related fixes/refactorings nodejs/node#55217

Closed

wraithgar mentioned this issue Nov 20, 2024

v10 deps updates #7922

Merged

wraithgar closed this as completed Nov 26, 2024

songyang-dev mentioned this issue Nov 26, 2024

[BUG] (node:63871) ExperimentalWarning: CommonJS module using require() #7942

Closed

2 tasks

[BUG] ExperimentalWarning: Support for loading ES Module in require() is an experimental feature and might change at any time #7857

[BUG] ExperimentalWarning: Support for loading ES Module in require() is an experimental feature and might change at any time #7857

Comments

alexsch01 commented Oct 18, 2024

Is there an existing issue for this?

This issue exists in the latest npm version

Current Behavior

Expected Behavior

Steps To Reproduce

Environment

shadowspawn commented Oct 18, 2024

MikeMcC399 commented Oct 19, 2024

MikeMcC399 commented Oct 19, 2024

MikeMcC399 commented Oct 19, 2024

RedYetiDev commented Oct 19, 2024

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