npm script command to run a script command from another package.json

Question

I have two separate projects that use npm - so I have both :
some_base_folder/projectA/package.json and some_base_folder/projectB/package.json

Answer 1

You should use --prefix.

npm run [command] --prefix path/to/your/other/folder

And for yarn:

yarn --cwd path/to/your/other/folder [command]

Answer 2

well it turns out to be quite simple:

"scripts": {
  test_projectA:"cd ../projectA && npm run-script test"
}

Answer 3

I ended up using:

"scripts": {
   "job": "cd ./sub && \"$npm_execpath\" run subjob",
   ...
}

because this also works with yarn.