npx -n on Windows broken since cmd-shim 3.x

[kevinbosman]

Since npm updated cmd-shim to v3.x (npm v6.11.0) it is no longer possible to pass node args to an pre-installed package via --node-arg/-n with Windows cmd.

This is due to the regex in findNodeScript() no longer matching the updated shims over here:

npx/index.js

Line 357 in 43d68c8

const cmd = /"%~dp0\\node\.exe"\s+"%~dp0\\(.*)"\s+%\*/

Reproduction steps

A simple example:

npm i uuid
npx -n -c uuid

This fails with:

ERROR: --node-arg/-n can only be used on packages with node scripts.

[tomyam1]

Still happens in npm@6.13.2

Works after going back to npm 6.10.3 and doing npm rebuild in the folder I'm trying to use npx

[Den-dp]

I really liked this feature.

It was handy for setting node options before npm package execution:

"scripts": {
  "start": "npx --node-arg=--max_old_space_size=4096 webpack-dev-server --mode development",
}

right now it looks way fragile (because I should know the wds package path)

"scripts": {
  "start": "node --max_old_space_size=4096 node_modules/webpack-dev-server/bin/webpack-dev-server --mode development"
}

[Den-dp]

Just found that accordingly to https://blog.npmjs.org/post/626173315965468672/npm-v7-series-beta-release-and-semver-major the new npm v7 will get a new npx implementation (look at npx section in this article).

And also this article states that:

The --node-arg and -n options are removed.

So it looks like this feature will be completely dropped 😕

[nathanblair]

Can it be documented more clearly exactly what the intention of npx/npm exec are for? At first it seemed like they were more or less a really functional alias for node node_modules/.bin. But now the ability to pass in node arguments is gone.

I feel like there's definitely a use case for them when it comes to being able to exec package cli tools without having to explicitly install the cli tool package or maintain the package as a devDependency when you only need the package for a single initialization command.

I'm thinking mostly this benefits projects like react, angular, and other front-end frameworks that leverage npx with their tool to initialize their framework into a directory and give the directory a template package.json that the developer can begin working with. I see a lot of value in npx here though admittedly it would be even nicer if the --node-args flag was still recognized.

[isaacs]

Since npx now supports all standard npm configs (with the exception that -p is a shorthand for --package instead of --parseable), you can use --node-options instead of --node-args for any options you need to pass to node.

Eg, instead of npx -c 'do-something' --node-args='--abort-on-uncaught-exception --harmony-top-level-await' you'd do npx -c 'do-something' --node-options='--abort-on-uncaught-exception --harmony-top-level-await'.

See: https://docs.npmjs.com/using-npm/config.html#node-options