fix: default brotliOptions does not applied to createBrotliCompress and createBrotliDecompress

[stanleyxu2005]

The problem

I encounted a remarkable performance slow down after migrating from Koa.
Although the doc mentions fastify/compress already sets the compression level to 4, but it takes too long to compress (3MB for 5 sec) a json. I guess it is configured unexpectedly by default.

After some investigation, it could be related to the previous merge request #278.
Unless I explicitly set the compression level to 4, I will get 11 (BROTLI_DEFAULT_QUALITY).

The root cause

The compression level is a member of brotliOptions.params not brotliOptions. https://nodejs.org/api/zlib.html#class-brotlioptions

And unfortunately the global default option is overwritten by custom option afterwards https://github.com/fastify/fastify-compress/blob/master/index.js#L129

The change

1. Proposed a fix with additional test cases included.
2. Added a new test case to ensure with default options, response will be compressed with level 4.
3. Changed the existing test case to speicfy the compression level to 8 and check if it is compressed expectedly.

Loop in author of previous commit @kahlstrm as well.

Checklist

• run npm run test and npm run benchmark
• tests and/or benchmarks are included
• documentation is changed or added
• commit message and code follows the Developer's Certification of Origin
  and the Code of conduct

[gurgunday]

lgtm

[gurgunday]

There is a type error... can you take a look?

#284 (comment)

[stanleyxu2005]

There is a type error... can you take a look?

@gurgunday I tried to understand the error, but have no clue why it is failed.

It expects to throw an type error for inject(). I dont see the callback is reachable. Strangely, I checkout the master branch it shows the same error, but the pipeline for previous commits on GitHub are successful. Could you help to figure out?

[stanleyxu2005]

After some more code reading, I made a follow-up change. The compress level will be set to 4 for the global option only. If route has its own compression options, it will be merged with global options anway. No need to double overwrite.

[mcollina]

Lgtm. but for some reasons our types tests are failing.

(This can’t land otherwise, and it seems not independent).

[stanleyxu2005]

I'm thinking if https://github.com/fastify/fastify-compress/blob/master/types/index.test-d.ts#L101-L112 is needed. I'm prefer to remove them

[gurgunday]

Can you try this?

appWithoutGlobal.inject(
  {
    method: 'GET',
    path: '/throw-a-ts-arg-error',
    headers: {
      'accept-encoding': 'gzip'
    }
  },
  (err) => {
    expectType<Error | undefined>(err) // add undefined
  }
)

[stanleyxu2005]

@gurgunday @mcollina by changing expectType<Error>(err) to expectType<Error | undefined>(err), all test errors are gone at my local env. Committed a new change, and hope all checks will be passed soon. 😆

[gurgunday]

Yeah seems like ts(d) behavior changed

I will release a new version of this package

[stanleyxu2005]

Yeah seems like ts behavior changed

I will release a new version of this package

Indeed. It's an interesting test error.

Thank you both for reviewing the code change.

This project is quite well coded and documented. I'm glad that I contributed some bugfix for it.👍

[gurgunday]

lgtm