feat: publish xlsx import export as separate wasm

[BrianHung]

Separates xlsx into its own wasm file to address bundle size increase concerns in #379.

Had to update wasm-bindgen to avoid a separate crate just for xlsx.wasm.

[nhatcher]

Hi @BrianHung,

This is definitely a good idea! And people have asked for this. Lets do it.

But I am not sure if we can use the xlsx crate as is, as that crate might grow in considerable size.

That being said my first problem is that building the wasm as per your instructions I actually get a smaller build! What am I doing wrong?

➜  wasm git:(xlsx) ✗ ls -all pkg/*.wasm
-rw-rw-r-- 1 nicolas nicolas 2395869 Jun 28 08:52 pkg/ironcalc_bg.wasm
-rw-rw-r-- 1 nicolas nicolas 2367828 Jun 28 08:52 pkg/xlsx_bg.wasm

[nhatcher]

Could you explain why we need all this?

[BrianHung]

xlsx are actually zip files, so we need to bundle the utility functions flate2 (for deflating a zip file) and time (timestamps in headers) along with it.

[nhatcher]

Or is it that you need both wasm files? That is an awesome feat! I was imagining you would have two builds:

• One of 2.4 Mb that is the old wasm
• A new one of 3.7 Mb that contains the model and the xlsx import/export

I have done that in the past and discarded for now as I didn't see an immediate benefit for IronCalc. But having two different packages is interesting as you could load the second one on demand only when importing/exporting.

[nhatcher]

I'm a bit curious about this, why didn't you go the same way as the other build? Note in Cargo you can have different build targets. See for instance in IronCalc:

https://github.com/ironcalc/IronCalc/blob/main/base/Cargo.toml#L24-L27

https://github.com/ironcalc/IronCalc/blob/main/base/src/model.rs#L38-L64

Maybe that would make things easier? We just have two builds with different features?

[BrianHung]

This is so we can have one crate, but two wasm files outputted.

If there isn't a main declaration, cargo would just treat it as a library and won't turn it into an artifact.

I'm pretty new to rust, so if you have a preferred method that achieves the same goal, I would defer to you here!

[nhatcher]

Hi @BrianHung, I left a few questions, mostly for my own understanding. Once I understand what is going on I would like to streamline the process a bit. But I think this is awesome!

[BrianHung]

But having two different packages is interesting as you could load the second one on demand only when importing/exporting.

Yep, that's right! We keep ironcalc and xlsx import/export as separate wasm files so we don't cause client to have an unnecessary larger bundle size if they don't use xlsx utilities.