Sending command line arguments to npm script
Problem
The scripts
portion of my package.json
currently looks like this:
"scripts": {
"start": "node ./script.js server"
}
...which means I can run npm start
to start the server. So far so good.
However, I would like to be able to run something like npm start 8080
and have the argument(s) passed to script.js
(e.g. npm start 8080
=> node ./script.js server 8080
). Is this possible?
Solution
Edit 2014.10.30: It's possible to pass args to npm run
as of npm 2.0.0
The syntax is as follows:
npm run
Note the necessary --
. It is needed to separate the params passed to npm
command itself and params passed to your script.
So if you have in package.json
"scripts": {
"grunt": "grunt",
"server": "node server.js"
}
Then the equivalent of
grunt task:target
run via npm would be
npm run grunt -- task:target
and the equivalent of
node server.js --port=1337
will be
npm run server -- --port=1337
Edit 2013.10.03: It's not currently possible directly. But there's a related GitHub issue opened on npm
to implement the behavior you're asking for. Seems the consensus is to have this implemented, but it depends on another issue being solved before.
Original answer: As a some kind of workaround (though not very handy), you can do as follows:
Say your package name from package.json
is myPackage
and you have also
"scripts": {
"start": "node ./script.js server"
}
Then add in package.json
:
"config": {
"myPort": "8080"
}
And in your script.js
:
// defaulting to 8080 in case if script invoked not via "npm run-script" but directly
var port = process.env.npm_package_config_myPort || 8080
That way, by default npm start
will use 8080. You can however configure it (the value will be stored by npm
in its internal storage):
npm config set myPackage:myPort 9090
Then, when invoking npm start
, 9090 will be used (the default from package.json
gets overridden).
Discussion
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