@para/transpile

Standalone transpiler for Para — turns .pts source into standard JavaScript that imports from the matching @para/* npm packages. No Parabun runtime required at build time.

The canonical Para transpiler lives inside the Parabun fork of Bun (Zig). This package is a TypeScript reimplementation, intended for projects that don't (or can't) install Parabun on their build host: browsers, Lambda, Cloudflare Workers, Deno, Node, the Para playground.

Status — IN DEVELOPMENT, not yet released

package.json is private: true and version 0.0.0-dev. We don't ship a partial transpiler — the npm publish gate stays closed until every Para desugaring listed below works end-to-end and matches the canonical Zig parser's output.

| Feature | Status | | --- | --- | | ..! / ..& (catch / finally chain operators) | ✅ | | \|> pipeline operator | ✅ | | .. / ..= ranges | ✅ | | pure keyword strip | ✅ | | signal NAME = EXPR; declaration | ✅ | | effect { … } block | ✅ | | when EXPR { … } / paired form | ✅ | | ~> / -> reactive bindings | ✅ | | defer / defer await | ✅ | | memo declarator | ✅ | | arena { … } block | ✅ | | bare-read sugar (x → x.get()) | ✅ | | signal x = expr-with-signals auto-promotes to derived | ✅ | | Parity test against canonical Zig parser output | ✅ (12/12 fixtures byte-equivalent after normalization) | | bun:wrap import injection for runtime helpers | ✅ | | using / await using polyfill (ES2022 target) | ✅ |

using polyfill

defer EXPR; and defer await EXPR; lower to ES2024 using / await using declarations, then a final pass rewrites those into a TS-style try/catch/finally block with __addDisposableResource and __disposeResources calls. The helper definitions are inlined at the top of any file that needs them, keeping the output self-contained without requiring a runtime import. Final output runs on Node 18 / 20 and every modern browser without requiring an additional downlevel pass from the host bundler.

Install

npm install @para/transpile
# Plus the @para/* runtime packages your code uses, e.g.:
npm install @lyku/para-signals @para/parallel @para/pipeline

Use

import { transpile } from "@para/transpile";

const js = transpile(`
  const handler = err => console.error(err);
  const result = fetch("/api").then(r => r.json()) ..! handler;
`);

// js is standard ES2022:
//   const handler = err => console.error(err);
//   const result = fetch("/api").then(r => r.json()).catch(handler);

CLI

para transpile src/main.pts > dist/main.js
para transpile < src/main.pts > dist/main.js

License

MIT