Switching from JSZip to unzipit

Sep 16, 20

This is about how I switched from using JSZip to unzipit in a javascript/spa application. I’ll show the before and after code that I use for decompressing a payload from a URL.

First a little context

I currently have a dashboard application that pulls some zipped data down, unzips it, and uses the json payload. There are reasons(tm) that I do this, but I was using JSZip to decompress the payload after a fetch, and then do stuff with it. The issue was the JSZip library was kind of large and in charge for me and tree shaking did not really seem to reduce the size even though I was only using the unzip portion. There may some wizardry to getting that to work, but my thoughts have been for a bit that I’d rather just find something that unzips only as that’s all I need. My thinking was also, from writing some compression/decompression code many years ago that this should not be so big. The payload I was getting by downloading the min file from cdn was 27.5k compressed and 95.8k as a resource size. Adding this via npm and hoping tree shaking would do it’s thing didn’t seem to reduce the size. I’m using rollup and this is going into a svelte project. I didn’t try just importing the file and hoping tree shaking would happen, but I just kept occassionally looking for another library. There were some promising ones but I didn’t find one that I liked. Until i stumbled across unzipit. In this case I just added the bundle and it only added ~8k to my total bundle size and i dropped the cdn for jszip. Their site says it (unzipit) is faster/better/etc and the goal seems to be exactly what I was looking for: a small unzip only javascript library.

From this…

To this…


Pretty simple. I like it so far and it’s working great in production with no issues. Seems faster although this operation is pretty small so I didn’t go into any benchmarking for it. Definitely smaller.