Optimistically cache tarballs when packages change?

[nolanlawson]

When you install lodash@^4.0.0, then local-npm will cache and store 4.0.0 for future npm installs.

However, if 4.0.1 is published after you npm install, then local-npm will find out about it via the changes feed, but it will not download the actual tarballs.

So if you then go offline and try to npm install again, it will fail because local-npm knows that there is a newer version that matches your version range, but it hasn't been downloaded yet.

Question: should local-npm optimistically cache every version of Lodash that gets published, simply because you once installed lodash@^4.0.0?

Pros: more likely to work offline, less likely to cause unexpected errors, fits the "standard" pattern of caret- and tilde-versioning.

Cons: Potentially a lot of network traffic and a lot of wasted disk spaces for module versions that you might never use.

[jesstelford]

I npm install a lot while tethering (side projects I work on while commuting). Even the existing changes feed make me nervous about going over my ridiculously low data cap.

I'd support optimistic tarball caching if it's configurable (and off by default).