Exclude test code in npm package?

One thing that I haven't been able to find explicitly mentioned anywhere is the fact that the "files" entry in package.json supports using a ! prefix on an entry. So, for example, I have a "files" entry that looks like this:

{
  "files": [
    "lib/**/*",
    "!lib/**/*.map"
  ],
}

I do that because my lib directory includes .map files that I don't want to include in the package, and this includes everything but the *.map files.

Another approach is to use a lib folder and store everything in there. Then you can configure your package.json to consider only that folder.

In order to work you need also to move your main file inside lib and specify it in the package.json. See example below:

{
  "name": "your-package",
  "main": "./lib/index.js",
  "files": [
    "/lib"
  ]
}

More info are available on this nice article

Yes that's what most people do, here are some npmignore files for popular Node.js modules:

https://github.com/socketio/socket.io/blob/ab46351a8446516fb4eea3b8333f7c0f18afaac5/.npmignore

Other people allowlist what they want published in their package.json files setting:

https://github.com/senchalabs/connect/blob/master/package.json
https://github.com/strongloop/express/blob/master/package.json