cross-var




Overview

When using npm scripts it creates a lot of environment variables that are available for you to leverage when executing scripts.

If you'd like to take a look at all of the variables then you can run npm run env in your terminal.

``
> npm run env

npm_package_name=cross-var
npm_package_author_name=Elijah Manor
npm_package_version=1.0.0
... lots more ...
`

Now you can use those environment variables in your npm scripts by referencing them like the following

`
{
"name": "World",
"scripts": {
"//": "The following only works on Mac OS X/Linux (bash)",
"bash-script": "echo Hello $npm_package_name"
"//": "The following only works on a Windows machine",
"win-script": "echo Hello %npm_package_name%"
}
}
`

`
> npm run bash-script

Hello World
`
However, this won't work on Windows... because it expects the variables to be surrounded by percent signs, so we can change our script just slightly.

$3

The goal of cross-var is to let you use one script syntax to work either on a Mac OS X/Linux (bash) or Windows. Reference the [Usage]() documention below on how to use cross-var in your scripts.

Usage

$3

`
{
"version": "1.0.0",
"config": {
"port": "1337"
},
"scripts": {
"prebuild": "cross-var rimraf public/$npm_package_version",
"build:html": "cross-var jade --obj data.json src/index.jade --out public/$npm_package_version/",
"server:create": "cross-var http-server public/$npm_package_version -p $npm_package_config_port",
"server:launch": "cross-var opn http://localhost:$npm_package_config_port"
}
}
`

$3

`
{
"version": "1.0.0",
"scripts": {
"build:css": "cross-var \"node-sass src/index.scss | postcss -c .postcssrc.json | cssmin > public/$npm_package_version/index.min.css\"",
"build:js": "cross-var \"mustache data.json src/index.mustache.js | uglifyjs > public/$npm_package_version/index.min.js\"",
}
}
`

But What About!?!

> Click on one of the following questions to reveal a detailed answer




Why don't you use cross-env?


cross-env is great for scripts that need a particular environment variable
set, but isn't intended to fix cross-environment issues when using variables
inside an npm script






Why don't you use an external node file?

That is a fine solution to this problem, but if you would rather stick to
straight up npm scripts, then this is a good solution






Why don't you just use Windows 10 Ubuntu-based Bash shell?

Yes, if you can do that... then great! Windows 10’s version 1607 update, dubbed the “Anniversary Update”, has intergrated a great bash shell that should allow you to run Linux software directly on Windows without any changes.

However, if you want to support older Windows versions, then you might consider using cross-env` or another approach to leverage environment variables in your scripts.