How to run npm sh script on Windows and Unix

Question

I want to run a sh script that detects my npm version via npm scripts . I have the following script and it works cool:

if [ $(npm -v | cut -c 1 | awk '{print $1\"<3\"}' | bc -l) != 0 ]; then echo '[ERROR] You need npm version @>=3\n' && false; fi

But this script works only on *NIX when I run the script on windows I got a error:

$(npm was unexpected at this time.

I want to detect if I'm running the script on Windows then don't execute the script, I tried this, but again only works on *NIX:

if [ 'uname -s' != CYGWIN* ]; then if [ $(npm -v | cut -c 1 | awk '{print $1\"<3\"}' | bc -l) != 0 ]; then echo '[ERROR] You need npm version @>=3\n' && false; fi; fi

Then I got:

'uname was unexpected at this time.

I was checking that the equivalent of uname on windows is systeminfo

But if I use systeminfo then I got the undefined on *NIX.

Any ideas of how can I make this script work on Windows && *NIX?

Answer 1

If you want to execute your bash script on a platform that is not Windows you could check the platform with node itself (assuming that node is installed) using os.platform()

scripts: {      
  checkNpmVersion: "node -e \"process.exit(require('os').platform() === 'win32')\" && ./check-npm.sh"
}

Or even better you could write your little script in node so that it works on any platform (again assuming that node is installed)

// check-npm.js
const exec = require('child_process').exec

exec('npm -v', function (err, stdout, stderr) {
  if (err) throw err
  if (stdout.match(/^3/)) throw "npm>3 required"
})

And in the scripts field

scripts: {      
  checkNpmVersion: "node check-npm.js"
}

Tested on Win7 with Node v4.4.5 and npm 2.15.5