Adds whether there are types for a package to an index

[orta]

Based on this discussion. This PR adds a new field to the JSON index for npm search

{
  ...
  "types": { "ts": "included" }
}

or

{
  ...
  "types": { "ts": "@types/lodash" }
}

and if they don't support it:

{
  ...
 "types": {  "ts": null }
}

which might be absent in JSON? Or false. Actually not sure. But definitely falsy.

Running yarn format did a few more changes than I would have done solo, but I'll leave comments in here about what I've changed.

Note: I've not been able to successfully run this locally against a set of packages, so right now it's somewhat ready for testing but not guaranteed to be shippable without risk. Should work tho - hah.

Adding comments now.

[Haroenv]

@mjackson, are you fine with us calling unpkg here this many times?

[Haroenv]

Would be cool if there were tests for the new code :) looking at it, i think we’ll be fine with the impact on indexing time

[orta]

It would do a head request to unpkg at most once per package given that it's likely the majority of packages don't have types, then I'd expect the majority of packages to do this

[Haroenv]

I think we should nest this inside a “types” property, so that if there’s interest, we can add flow & reason eg

[orta]

Makes sense - it does that now, and has tests 👍

[robb]

null might be a more convenient alternative to undefined, given that the latter isn't available in JSON…

[orta]

Yeah, great point - fixed!

[arcanis]

The only caveat is that the index for foo won't be recomputed when a new @types/foo package appears, am I correct? It will require to publish a new version of foo 🤔

[Haroenv]

There’s a weekly refresh of the whole index to catch things like this. I guess we could add some extra code to schedule an update of the relevant package of an @types but it’s not that big of an issue I think

[mjackson]

@Haroenv I'm 👍 with calling unpkg like this. I'll let y'all know as soon as I launch a better way to do this than making HEAD requests...

[Haroenv]

Perfect 👌 I’ll take a look at if this works well next week

[Haroenv]

@orta I don't seem to be able to commit my comments, can you do it or give access to the repo? I'd like to try it out live

[Haroenv]

hah, faster than my comment

[orta]

👍

[karlhorky]

Awesome, merged! 🙌

I guess the next step to get this online is for someone to do a PR to yarnpkg/website as per
@arcanis' tweet?

And then something for the npm website too?

cc @mxstbr

[Haroenv]

Yes, the next step would be to add this to the website since it's now fully indexed

[Haroenv]

https://github.com/yarnpkg/website/blob/master/js/src/lib/Details/Aside.js here probably

[Haroenv]

Looks like something went wrong here still, I'll investigate, but the whole index has ts: null as the types key

[orta]

Doh!