Add 'br' encoding

[silverwind]

Noticed that the greatest encoding out there was missing from this list.

[silverwind]

Also, according to https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Content-Encoding, there's a possibilty for compress encoding, but I don't think this is worth adding here.

[kevva]

Is it worth adding a test for this maybe? Could use https://www.npmjs.com/package/brotli.

[silverwind]

That would add a devDep on https://github.com/mayhemydg/iltorb, which requires a native module. I don't think it's worth that as gzip is already tested.

[kevva]

How do we decompress the br content? Seems like zlib (which we are using in decompress-response) doesn't.

[silverwind]

How do we decompress the br content?

iltorb can both compress and decompress.

[kevva]

Yeah, but I mean when using got and you try to fetch br encoded content, it wouldn't be decompressed if decompress is true. We're only handling gzip and deflate I think. Not that it affects this PR, but it might be worth handling it?

[silverwind]

Oh, right. Looks like https://github.com/sindresorhus/decompress-response is lacking support for br. I guess it should be added there first.

[kevva]

The module I linked further up should handle it without native deps I think, https://github.com/devongovett/brotli.js.

[silverwind]

Haven't seen that one yet, but iltorb is well maintained and I haven't had any issues with it yet, even under Windows. Brotli compression is very CPU intensive, so I'd definitely compare the performance before choosing a module.

[kevva]

Yup, I'll work on a PR, but I'm willing to sacrifice performance over native deps tbh depending on the impact.

[silverwind]

Opened sindresorhus/decompress-response#12 which blocks this issue.

[sindresorhus]

sindresorhus/decompress-response#13 (comment)

[sindresorhus]

Node.js issue about adding it natively: nodejs/node#18964