How npm install works

Question

I use Node.js (via browserify) for each of my web apps, all of which have some dependencies in common and others specific to themselves. Each of these apps has a package.j

Answer 1

When I run npm install inside an app folder, however, it appears to install everything locally regardless of where else it may exist upstream. Is that the correct behavior? (It's possible there's another reason, like bad version language in my package.json). If this IS the correct behavior, is there a way for me to have npm install behave like the above?

Yes, that is what npm install does. In node.js code, the require algorithm has a particular sequence of places it looks, including walking up the filesystem. However, npm install doesn't do that. It just installs in place. The algorithms it uses are all constrained to just a single node_modules directory under your current directory and it won't touch anything above that (except for with -g).

It's not a big deal to widely replicate the modules inside every app, but it feels messy and prevents me from make small improvements to the common modules and not having to update every old package.json file. Of course, this could be a good thing...

Yeah basically you're doing it wrong. The regular workflow scales well to the Internet. For your use case it creates some extra tedious work, but you can also just use semantic versioning as intended and specify "mylib": "^1.0.0" in your package.json for your apps and be OK with automatically getting newer versions next time you npm install.