Syntax (windows and linux) for multiple commands using Node cross-env - node.js

Question

I'm taking a look at a project that has this line in it's package.json to run Karma tests
"scripts": {
"test": "NODE_ENV=test karma start karma.conf.js",
This doesn't work in Windows when I try "npm test".
I gather this is because this is a *nix syntax. And, in fact, if I change it to
"scripts": {
"test": "set NODE_ENV=test && karma start karma.conf.js",
the tests start when I run npm test.
Looking around, the optimal solution appears to be to use the cross-env package and rewrite it like
"scripts": {
"test": "cross-env NODE_ENV=test && karma start karma.conf.js",
So I get the cross-env will take care of the "set NODE_ENV" part to work on multiple OSes, but it's the "&&" part I'm questioning.
Do I leave the "&&" between the commands when using cross-env? Will that work in windows and linux?

Answer 1

Your cross-env example won't work, it should just be:
"scripts": {
"test": "cross-env NODE_ENV=test karma start karma.conf.js",
without the &&. The command to run comes immediately after you're done setting the variables.
I found your question by searching for how to set multiple variables with cross-env and also how to run multiple scripts/commands with cross-env. So to address the "multiple commands" part of your question:
Given these 2 test scripts:
a.js
console.log('a', process.env.TEST_VAR, process.env.TEST_VAR_2);
b.js
console.log('b', process.env.TEST_VAR, process.env.TEST_VAR_2);
You'll find if you have an && in the script in your package.json the subsequent scripts don't receive the variables. For example:
"scripts": {
"check": "cross-env TEST_VAR=hello TEST_VAR_2=world node a.js && node b.js",
Running npm run check gives:
a hello world
b undefined undefined
You can solve this by having an extra script which runs the multiple commands and running that with cross-env:
"scripts": {
"check": "cross-env TEST_VAR=hello TEST_VAR_2=world npm run check-real",
"check-real": "node a.js && node b.js",
Now npm run check gives:
a hello world
b hello world