This directory defines a Rust crate that can be compiled to WebAssembly. It is intended to power an interactive demo on the webpage.
To build the module and bindings with Nix:
$ nix build .#wasm --out-link result
$ ls -l $(realpath result)
total 292
-r--r--r-- 1 root root 289692 Jan 1 1970 rcl_bg.wasm
-r--r--r-- 1 root root 6526 Jan 1 1970 rcl.js
If you don't want to build with Nix, follow the steps below instead.
The devshell in the Nix flake includes the required wasm-bindgen and
wasm-opt from Binaryen. You will also need the
wasm32-unknown-unknown target. It is not by default part of
rust-toolchain.toml because the non-nightly toolchain is of no use for
producing small binaries. Add it manually:
rustup target add wasm32-unknown-unknown
Build a large-ish binary with the regular toolchain:
cargo build \
--manifest-path wasm/Cargo.toml
--profile=release-wasm \
--target=wasm32-unknown-unknown \
Build a much smaller binary, but requires nightly:
cargo +nightly build --lib \
--manifest-path wasm/Cargo.toml \
--profile=release-wasm \
--target=wasm32-unknown-unknown \
-Z build-std=std,panic_abort \
-Z build-std-features=panic_immediate_abort
Shrink the binary further with wasm-opt from Binaryen:
wasm-opt -Oz \
target/wasm32-unknown-unknown/release-wasm/rcl_wasm.wasm \
--output target/rcl.wasm
Inspect the wasm file to confirm it doesn't contain needless fluff:
wasm-dis target/rcl.wasm
Generate the Javascript bindings:
wasm-bindgen \
--out-dir target/web \
--target no-modules \
--no-typescript \
target/rcl.wasm
Concatenate the required source files (“bundling”) and minify them if desired:
cat wasm/src/rcl_dom.js target/web/rcl.js | esbuild --minify > target/web/bundle.js
mv target/web/{bundle,rcl}.js
Put everything together:
cp wasm/index.html target/web
python -m http.server --directory target/web