Adding zsh ternary operator in npm script - bad subsitution - zsh

Question

I am wanting to use a ternary operator in my npm script:
"scripts": {
"build" "node ${%(ENVVAR=nope.foo.bar)}.js"
}
So that I can use it like:
ENVVAR=nope yarn build
And obtain the resulting command of:
"node foo.js"
However my attempts above (tried parens and square brackets) always yield bad substitution
What is the proper syntax to include a ternary operator in my parameter expansion for this (zsh shell)

Answer 1

The npm docs state:
"The actual shell your script is run within is platform dependent. By default, on Unix-like systems it is the /bin/sh command, on Windows it is the cmd.exe. The actual shell referred to by /bin/sh also depends on the system. As of npm#5.1.0 you can customize the shell with the script-shell configuration."
Therefore given that the shell npm utilizes on *nix is typically sh consider the following npm script instead (Unless of course your npm's script-shell has actually been configured to zsh):
"scripts": {
"build": "[[ $ENVVAR = \"nope\" ]] && val=foo || val=bar; node \"${val}.js\""
}
Note: You can check which shell npm is utilizing via the npm config command: npm config get script-shell
Alternatively, for cross-platform regardless of which shell npm is configured to utilize, consider evaluating a node.js script inline which "shells-out" the node ... command. For example the following (albeit somewhat verbose) npm script utilizes execSync:
"scripts": {
"build": "node -e \"const val = process.env.ENVVAR === 'nope' ? 'foo' : 'bar'; require('child_process').execSync('node ' + val + '.js', { stdio: [0,1,2] })\""
}