NPM package 'bin' script for Windows - windows

Question

Cucumber.js is supplying a command-line "binary" which is a simple .js file containing a shebang instruction:
#!/usr/bin/env node
var Cucumber = require('../lib/cucumber');
// ...
The binary is specified in package.json with the "bin" configuration key:
{ "name" : "cucumber"
, "description" : "The official JavaScript implementation of Cucumber."
// ...
, "bin": { "cucumber.js": "./bin/cucumber.js" }
// ...
This all works well on POSIX systems. Someone reported an issue when running Cucumber.js on Windows.
Basically, the .js file seems to be executed through the JScript interpreter of Windows (not Node.js) and it throws a syntax error because of the shebang instruction.
My question is: what is the recommended way of setting up a "binary" script that works on both UNIX and Windows systems?
Thanks.

Answer 1

Windows ignores the shebang line #!/usr/bin/env node and will execute it according to the .js file association. Be explicit about calling your script with node
node hello.js
ps. Pedantry: shebangs aren't in the POSIX standard but they are supported by most *nix system.
If you package your project for Npm, use the 'bin' field in package.json. Then on Windows, Npm will install a .cmd wrapper along side your script so users can execute it from the command-line
hello
For npm to create the shim right, the script must have the shebang line #!/usr/bin/env node

Answer 2

your "bin" should be "cucumber" npm will create a "cucumber" or "cucumber.cmd" file pointing to "node %SCRIPTNAME%". the former being for posix environments, the latter being for windows use... If you want the "js" to be part of the executable name... you should use a hyphon instead... "cucumber-js" ... Having a .js file will come before the .js.cmd in your case causing the WScript interpreter to run it as a JScript file, not a node script.
I would suggest looking at coffee-script's package.json for a good example.
{
"name": "coffee-script",
"description": "Unfancy JavaScript",
"keywords": ["javascript", "language", "coffeescript", "compiler"],
"author": "Jeremy Ashkenas",
"version": "1.4.0",
"licenses": [{
"type": "MIT",
"url": "https://raw.github.com/jashkenas/coffee-script/master/LICENSE"
}],
"engines": {
"node": ">=0.4.0"
},
"directories" : {
"lib" : "./lib/coffee-script"
},
"main" : "./lib/coffee-script/coffee-script",
"bin": {
"coffee": "./bin/coffee",
"cake": "./bin/cake"
},
"scripts": {
"test": "node ./bin/cake test"
},
"homepage": "http://coffeescript.org",
"bugs": "https://github.com/jashkenas/coffee-script/issues",
"repository": {
"type": "git",
"url": "git://github.com/jashkenas/coffee-script.git"
},
"devDependencies": {
"uglify-js": ">=1.0.0",
"jison": ">=0.2.0"
}
}

Answer 3

I managed to figure out a solution to a similar issue.
My original plan was to have only one large .js file, for both the API and CLI (the reason is because I didn't know how to share variables between two files at the time). And when everything was built, I tried to add the #!/usr/bin/env node shebang to my file. However that didn't stop Windows Script Host from giving an error.
What I ended up doing was coming up with an idea of a "variable bridge" that allowed variables to be read and set using getVar and setVar. This made me have to extract the CLI code from the API code and add some imports to the variable bridge.
In the CLI file, I added the shebang, and modified the package.json of my project to have:
{
...
"main": "./bin/api.js",
"bin": {
"validator": "./bin/cli.js"
}
...
}
Here are a few small notes that I think might help if Windows Script Host is still giving an error (I applied all of them so I'm not sure which one helped):
Using only LF line endings seemed to help.
It seems that ./bin is the preferred directory for compiled files. I did try ./dist but it didn't work for me.
An empty line after the shebang may be needed:
// cli.js
#!/usr/bin/env node
// code...
Using the same name for main and bin in package.json seemed to be an issue for me.