oxidil

A JavaScript / TypeScript optimizing compiler — the Rust oxidil crate (built on the oxc ecosystem) compiled to WebAssembly and wrapped in a typed Node API and CLI.

It parses JS/TS, optionally strips TypeScript types, runs a set of sound optimization passes gated by a GCC-flavored -O level, and emits optimized JavaScript plus a v3 source map. Everything runs in-process inside the WASM module — no node/terser/esbuild/swc is shelled out to.

Install

npm install oxidil

Requires Node.js >= 18. The WebAssembly module is bundled — there is no native build step at install time.

API

import { compile } from "oxidil";

const { code, map } = compile("const a = 1 + 2 * 3;\nconsole.log(a);\n", {
  level: "2",
  sourceMap: true,
});

console.log(code); // "const a = 7;\nconsole.log(a);\n"

compile(source, options?) => { code, map? }

| Option | Type | Default | Meaning | |--------|------|---------|---------| | filename | string | "input.js" | Source type is inferred from the extension (.js .jsx .mjs .cjs .ts .tsx); also used as the sources entry of the map. | | level | "0"\|"1"\|"2"\|"3"\|"s"\|"z" (or 0–3) | "2" | Optimization level (see below). | | tsTypeof | boolean | false | Enable the ts-typeof-elimination pass (effective only at level >= 1). | | enable | string[] | [] | Force-include passes by id even if the level gates them off. | | disable | string[] | [] | Force-exclude passes by id. Disable wins over enable. | | sourceMap | boolean | false | Produce an output v3 source map (returned as map, a JSON string). | | inputSourceMap | string | — | JSON of an input map; the output map is composed back to the original sources. |

CLI

oxidil <INPUT> --out <FILE> [--out-map <FILE>] [--source-map <FILE>]
        [-O<level>] [--ts-typeof]
        [--enable <ID>]... [--disable <ID>]...

npx oxidil app.ts --out app.js --out-map app.js.map -O2

| Flag | Meaning | |------|---------| | <INPUT> | Input file. Source type inferred from extension. | | --out <FILE> | Required. Where optimized JS is written. | | --out-map <FILE> | Where the output source map is written (and a //# sourceMappingURL= comment is appended). | | --source-map <FILE> | Input source map for <INPUT>; the output map is composed back to the original sources. | | --ts-typeof | Enable ts-typeof-elimination. | | -O0/-O1/-O2/-O3/-Os | Optimization level (default -O2). -O == -O1, -Oz == -Os. Aliases -0..-3/-s and --O0..--Os also work. | | --enable <ID> / --disable <ID> | Force a pass on/off (repeatable; disable wins). |

Exit codes: 0 ok, 1 parse error, 2 IO error, 64 usage error.

Optimization levels

| Level | Passes | |-------|--------| | -O0 | None (parse → type-strip if TS → passthrough). | | -O1 | Constant folding + peephole/algebraic. | | -O2 (default) | -O1 + dead-code elimination at full fixpoint. | | -O3 | -O2 with a higher fixpoint cap (more aggressive). | | -Os / -Oz | -O2 + identifier minify/rename + compact codegen (size). |

Building from source

The published package ships prebuilt WASM. To rebuild it you need the Rust toolchain plus wasm-pack. The version lives in the crate's Cargo.toml (the source of truth); npm/package.json and npm/src/version.ts are generated from it and are gitignored — so build from the repo root with make:

make npm     # generates the version files, then runs wasm-pack + tsc

Or, if the generated files already exist (make generate):

npm run build        # build:wasm (wasm-pack) + build:ts (tsc)
npm test

License

MIT