[BUG] npm-run-script "-- --flag=value" args intercepted as npm config on Windows but not on Linux

[xSuiteKevinSartiano]

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 running npm run <script> -- --foo=bar on Windows, npm intercepts --foo as an unknown CLI config option and strips it from the arguments passed to the script. The script receives no arguments.

> npm run debug -- --foo=bar  
npm warn Unknown cli config "--foo". This will stop working in the next major version of npm.

> my-package@1.0.0 debug
> echo param:

param:

Expected Behavior

Arguments after -- should be forwarded as-is to the script. This is the expected behavior observed on Linux:

$ npm run debug -- --foo=bar

> my-package@1.0.0 debug
> echo param: --foo=bar

param: --foo=bar

Steps To Reproduce

1. In a Windows environment
2. Create a package.json with a simple script:

   {
     "scripts": {
       "debug": "echo param:"
     }
   }

3. Run npm run debug -- --foo=bar
4. See error npm warn Unknown cli config "--foo". This will stop working in the next major version of npm. and that no params is printed to console.

Environment

• npm: npm@11.14.1
• Node.js: node@v24.13.0
• OS Name: Windows 11 Enterprise
• System Model Name: Dell Precision 3581
• npm config:

; "user" config from C:\Users\***\.npmrc

before = "2026-05-10T14:12:30.871Z"
ignore-scripts = true
min-release-age = 3

; node bin location = C:\Program Files\nodejs\node.exe
; node version = v24.13.0
; npm local prefix = C:\Users\***\Desktop\npm-debug
; npm version = 11.14.1
; cwd = C:\Users\***\Desktop\npm-debug
; HOME = C:\Users\***
; Run `npm config ls -l` to show all defaults.

[Giaxasidis]

@xSuiteKevinSartiano The issue is that on Windows, npm parses arguments after -- differently due to how the Windows command line tokenizes arguments. Flags like --foo=bar are being interpreted as npm configuration options rather than being passed through to the script. This does not happen on Linux because the shell handles argument parsing differently.

A workaround is to pass arguments without the -- prefix, or to escape them:

npm run debug -- ---foo=bar

or

npm run debug -- -- --foo=bar

The second approach adds an extra -- which tells npm to stop parsing flags entirely.

The proper fix requires changes to npm's argument parser on Windows to align with POSIX behavior. Specifically, arguments after the first -- should be passed through without any parsing, regardless of platform. This is a known inconsistency in npm's Windows compatibility.

[supermassive]

Is it a regression of #3136

[alexsch01]

I'm not getting this error on these versions

Nodejs 26.3.0 (includes npm 11.16.0)
Nodejs 24.13.0 (includes npm 11.6.2)

It prints param:--foo=bar

[xSuiteKevinSartiano]

@KaloudasDev your suggestion works, thanks!

npm run debug -- -- --foo=bar

@alexsch01
in which terminal did it work for you?
Mine fails on PowerShell 5.1.26100.8115

[alexsch01]

@xSuiteKevinSartiano how did you install nodejs and npm?

I'm using Windows Powershell as well and I can't reproduce the issue :(

[xSuiteKevinSartiano]

@alexsch01 I didn't install it. It came pre-installed with Windows (it runs within the Windows Terminal app) Sorry I misread. I installed nodejs and npm via nvm

nvm install 24
nvm use 24.13.0

then upgraded npm

npm install -g npm@11.14.1

Assuming you are trying to reproduce using my example in the issue description, when you run npm run debug -- --foo=bar it outputs echo npm-cli param: --foo=bar?

[alexsch01]

@xSuiteKevinSartiano why did you close this issue?

[xSuiteKevinSartiano]

@alexsch01 because there was no response for a few days and the workaround proposed from KaloudasDev works for me.
If that was incorrect procedure I apologize, I don't have much experience with opening issues.
I couldn't find any guidelines on how and when to close them

[alexsch01]

then upgraded npm

npm install -g npm@11.14.1

@xSuiteKevinSartiano @KaloudasDev this is the issue

when you do npm install -g npm@11.14.1 with nvm use 24.13.0, it overrides the npm.ps1 file directly in the prefix that NodeJS is installed to

• this uses https://github.com/npm/cmd-shim project which is not how Nodejs bundles npm in its install

> nvm use 24.13.0
> dir -n $(npm config get prefix)
node_modules
CHANGELOG.md
corepack
corepack.cmd
install_tools.bat
LICENSE
node.exe
nodevars.bat
npm
npm.cmd
npm.ps1
npx
npx.cmd
npx.ps1
README.md

it will show you where node.exe and npm.ps1 files live at

---

basically, reinstall Nodejs with nvm and don't use npm install -g npm with nvm