Speed up build

[Rich-Harris]

It takes forever to build the site, and I suspect there are some easy things we could do to speed it up but I don't know what they are (caching the twoslash transformer? caching the Marked instance?)

[dummdidumm]

I remember building the site being very fast - I'm wondering if this is related to the snippet cache change leading to constant misses in CI

[Rich-Harris]

It could be. I wonder if mtime isn't stable between runs for some reason. We can add some logging to see.

Definitely don't want to go back to a world of stale snippets though, so if that is the case then we'll need to start checking them in.

[trueadm]

If mtime isn't stable, could we instead use checksums of the snippet content?

[Rich-Harris]

The mtime refers to the code that generates the snippets

[Rich-Harris]

confirmed via #309 that the snippet cache is invalidated each time. we will need to check stuff in

[dummdidumm]

Instead of using the mtime, what about using the commit hash associated with the file that contains the generated code?

[Rich-Harris]

There are multiple files that could change — would we also need to figure out which commit was most recent?

[dummdidumm]

We can try how it works with #312

[dummdidumm]

Another idea if the commit time doesn't work out: hash of all the file contents in question.

Might be even better because it'll also purge the cache when you change stuff locally but didn't commit it yet

[Rich-Harris]

yeah, that could work. no substitute for statting the node_modules directory, but including the lockfile in the hash should be sufficient

[Rich-Harris]

i'm sure there are other things we can do, but i merged #315, this is good enough for now