The right thing is a machine-global package cache that can hold multiple versions of each package, and loader machinery that can pick out the right ones. That m

The right thing is a machine-global package cache that can hold multiple versions of each package, and loader machinery that can pick out the right ones. That means you only have to download and store each package once, and you never get interference between projects. NPM installs (and downloads?) a copy of each package for each project. This is the wrong thing to do.