[Idea]: allow setting the compression level

[matteosacchetto]

I was investigating the code of this library, and I've seen that it takes advantage of node:zlib's deflateRaw class/functions.

Given that zlib's compression methods typically accept a parameter which is the compression level (between 1 and 9, defaults to 6), I was wondering if it could be interesting/worth exposing that parameter. It would allow a user of the library, to tune the compression level based on time/disk space.

To implement it, I think we could do one of the following:

• entry.compress: instead of restricting it to be a boolean, we could allow it to be a boolean | number, where if it is a false or 0, no compression, if it is true, default compression level, otherwise the level is set based on entry.compress
• entry.level: have an additional parameter which specifies the level

I do not know how many users could be interested in this kind of feature, so I am leaving it here just as an idea, hoping to get some feedback from library users

[thejoshwolfe]

great idea! easy to support.

[thejoshwolfe]

published in version 3.2.0

[matteosacchetto]

Great to hear that!
I was checking the PR and I have a quick question

yazl/index.js

Lines 97 to 99 in dc85d0b

	zlib.deflateRaw(buffer, {level:1}, function(err, compressedBuffer) {
	setCompressedBuffer(compressedBuffer);
	});

In the addBuffer method (the lines highlighted above), I see that the level is set to 1. Shouldn't it be entry.compressionLevel? Or is there a reason for the fixed value?

Thank you in advance!

[thejoshwolfe]

Good catch! that's a typo. oops. I even have a test that makes sure the compression level is passed to zlib, but i only tested it for addFile() 🤦

fix published in 3.2.1.