Large .wasm file size with Rust

[adenflorian]

🐛 bug report

When importing a .rs file from a .js file, and building the js file with parcel build index.js, the resulting wasm file is much larger than expected.

dist\lib.c67b7947.wasm    ‼  1.4 MB    22ms
dist\index.js.map            5.9 KB     5ms
dist\index.js               3.11 KB    39ms

🤔 Expected Behavior

I would expect the wasm file to be closer to 200 KB or less.

😯 Current Behavior

The wasm file is 1.4 MB.

💻 Code Sample

https://github.com/AdenFlorian/parcel-rust-size-test

🌍 Your Environment

Software	Version(s)
Parcel	1.12.3
Node	10.15.1
npm/Yarn	yarn 1.17.3
Operating System	Windows 10

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed in 30 days if no further activity occurs. Thank you for your contributions.

[agusbena]

You can add these to your he Cargo.toml:

[profile.release]
lto = true
opt-level = 's'

And it will go, in my case, from 1.7Mb to 189Kb
Note it is for release profile, it will take effect when you do:

parcel build [your_entry_point_file.ext]