Running npm script on windows starting with a period - windows

Question

I have a package.json file with the following script defined:
"scripts": {
"test": "./node_modules/selenium-cucumber-js/index.js"
}
When I run npm test on linux or mac this script runs as expected. On Windows however I get an error:
/node_modules/selenium-cucumber-js/index.js
'.' is not recognized as an internal or external command,
operable program or batch file.
npm ERR! Test failed. See above for more details.
However if I run the command ./node_modules/selenium-cucumber-js/index.js directly from a cmd prompt it works correctly. The same issue also occurs if I try to run any other script through npm that starts with a ".". I haven't been able to find any other thread talking about this as an issue.
I am running npm versions 5.6.0 on Windows 10 Home.
Does anyone know how I can get this working?

Answer 1

Since npm 5.1
npm config set script-shell "C:\\Program Files (x86)\\git\\bin\\bash.exe"
or (64bit installation)
npm config set script-shell "C:\\Program Files\\git\\bin\\bash.exe"
Note that you need to have git for windows installed.
You can revert it by running:
npm config delete script-shell

Answer 2

Everything defined under scripts gets executed in the default system shell and on Windows ./node_modules/selenium-cucumber-js/index.js is definitely not a valid command (or rather a path). It just happens that the same file has a +x argument and a shebang pointing to a Node.js (or another JS interpreter) binary so that it gets executed on Linux without intervention.
I'm quite certain you'll get the same error if you were to execute the same command in the default Windows shell (cmd.exe) but you may get away with it in some ports/emulations of *nix shells (i.e. Cygwin, MSYS, bash.exe etc.) which may give you a false sense of everything working correctly outside of the npm chain.
If you want to make sure your script gets executed by Node.js while using relative paths and keeping cross-platform compatibility, call it explicitly as:
"scripts": {
"test": "node ./node_modules/selenium-cucumber-js/index.js"
}
This will also take care of things like not having a proper x flag or shebang in the script you're executing and since Node.js is perfectly comfortable with using *nix paths on Windows it won't complain either.

Answer 3

Whenever you write a shell script, you need to specify which shell it is written for. For inline package.json scripts, you should do this in an .npmrc alongside your package.json, like this:
script-shell = bash
If you don't specify a shell, npm is free to pick any old shell. On Windows, it picks cmd.exe, which is almost never what you want.
(Note: I don't recommend using npm config set for this. It sets local user configuration. The correct shell should be stored in version control alongside your scripts.)