Compiling to SWC

Learn how to compile your ReluxScript plugins to SWC (Rust) plugins.

Basic Compilation

Compile a .lux file to SWC:

relux build my-plugin.lux --target swc

This generates dist/lib.rs - a Rust module that implements the SWC VisitMut trait.

Output Format

The generated SWC plugin follows the standard SWC visitor pattern:

pub struct MyPlugin;

impl VisitMut for MyPlugin {
    fn visit_mut_call_expr(&mut self, node: &mut CallExpr) {
        // Your transformation logic
    }
}

Using with SWC

The generated Rust code can be:

1. Compiled to a native library for use in Rust projects
2. Compiled to WASM for use in JavaScript tooling

As a Rust Library

Add to your Cargo.toml:

[dependencies]
swc_common = "0.33"
swc_ecma_ast = "0.110"
swc_ecma_visit = "0.96"

Then use the visitor:

use swc_ecma_visit::VisitMutWith;
let mut visitor = MyPlugin;
program.visit_mut_with(&mut visitor);

As WASM

Compile to WebAssembly (requires additional setup):

cargo build --target wasm32-wasi --release

Use in SWC config:

{
  "jsc": {
    "experimental": {
      "plugins": [
        ["./plugin.wasm", {}]
      ]
    }
  }
}

Custom Output Directory

Specify a different output directory:

relux build my-plugin.lux --target swc --output build

This generates build/lib.rs instead of dist/lib.rs.

Compile Both Targets

Compile to both Babel and SWC simultaneously:

relux build my-plugin.lux --target both

Or omit --target (defaults to both):

relux build my-plugin.lux

This generates:

• dist/index.js (Babel)
• dist/lib.rs (SWC)

Next Steps

• Compile to Babel
• View Examples