zx doesn't seem to work as part of a node bin script

[bkjohnson]

I'm trying to have a zx script that feels like a more traditional cli tool, meaning that it is installed to the PATH so that a user can run it by just typing my-cli command --opts instead of zx path/to/my-script.mjs. To do this I'm using the package.json bin property. Here's the gist of my package.json:

{
  "name": "my-cli",
  "version": "0.0.1",
  "bin": {
    "my-cli": "./index.js"
  },
  "dependencies": {
    "zx": "^8.0.2"
  }
}

And my index file is doing something very basic:

#!/usr/bin/env zx

void (async function main() {
  const branch = await $`git branch --show-current`;
  echo(branch);
})();

From the package directory if I install this globally with npm install -g . I end up with the script in /usr/bin which is what I expect. However, I get a permissions error when I try to run it because zx is trying to open a .mjs file for writing.

[Error: EACCES: permission denied, open '/usr/bin/my-cli.mjs'] {
  errno: -13,
  code: 'EACCES',
  syscall: 'open',
  path: '/usr/bin/my-cli.mjs'
}

I think I've found out where it's coming from:

zx/src/cli.ts

Lines 160 to 169 in 0eb81c9

	if (ext === '') {
	const tmpFilename = fs.existsSync(`${filepath}.mjs`)
	? `${basename(filepath)}-${randomId()}.mjs`
	: `${basename(filepath)}.mjs`
	return writeAndImport(
	await fs.readFile(filepath),
	join(dirname(filepath), tmpFilename),
	origin
	)

tmpFilename is '/usr/bin/my-cli.mjs', and then we try to write the contents of the original script to it:

zx/src/cli.ts

Lines 144 to 155 in 0eb81c9

	async function writeAndImport(
	script: string | Buffer,
	filepath: string,
	origin = filepath
	) {
	await fs.writeFile(filepath, script.toString())
	try {
	await importPath(filepath, origin)
	} finally {
	await fs.rm(filepath)
	}
	}

One of my questions is why is it necessary to write to a new .mjs file? Am I trying to use zx in too unexpected of a way? This kind of setup would work without issue for a regular node script, so I wouldn't think that this would be such an edge case.

[antongolub]

You can avoid bin composition inside your script. As a workaround for now:

#!/usr/bin/env node
import 'zx/globals'

void (async function main() {
  const branch = await $`git branch --show-current`;
  echo(branch);
})();

[bkjohnson]

Thank you, that worked! Is there any downside or "gotcha" to this approach?