fizzygum-coffeescript-min

A minimal, compile-only build of CoffeeScript for the browser — a size-trimmed fork of CoffeeScript 2.0.3 that emits byte-for-byte identical JavaScript to the stock compiler for the language subset it supports, in a single self-contained UMD ~19% smaller than the stock browser distribution and free of the Babel-ES5 shim.

Built for the Fizzygum runtime, which compiles its ~470 class sources in the browser at boot and needs exactly one function: CoffeeScript.compile(source, { bare: true }). Everything the stock browser bundle ships for the CLI / <script type="text/coffeescript"> / source-map use cases is dead weight in that setting. This build removes it.

| | size (minified) | |---|---| | stock CoffeeScript 2.0.3 browser bundle (Babel-ES5) | 257,123 bytes | | fizzygum-coffeescript-min | ~208,554 bytes (−18.9%) |

Use

Browser — a classic <script> sets the CoffeeScript global:

<script src="dist/coffeescript.js"></script>
<script>
  var js = CoffeeScript.compile('add = (a, b) -> a + b', { bare: true });
</script>

Node — it is also require-able:

const CoffeeScript = require('fizzygum-coffeescript-min');
CoffeeScript.compile('x = 1', { bare: true }); // "var x;\n\nx = 1;\n"
CoffeeScript.VERSION;                           // "2.0.3"

The public surface is deliberately just compile and VERSION. There is no run, eval, register, nodes/tokens guarantees, source maps, or file I/O.

What's removed (and why it's safe)

Everything removed is unreachable for compile-only, { bare: true }, no-filename usage. Removals were verified two ways: (1) a byte-identity check — the fork's emitted JS is diffed against stock 2.0.3 for the whole corpus and must be empty; (2) empirical V8 coverage over a real compile of the whole corpus, to confirm the removed code never executes.

• Whole modules never on the compile path: browser.js (XHR loading, text/coffeescript, CoffeeScript.load/run, btoa), cake.js, command.js, optparse.js (CLI), repl.js, register.js (Node require hook).
• Babel-ES5 transpilation — targets modern JS (current Chrome / Safari), not ES5.
• Source maps — sourcemap.js, base64encode, the map-building inside compile(), the inlineMap/sourceMap/transpile return branches. (The emitted js never depended on them.)
• Error.prepareStackTrace monkey-patch, getSourceMap, formatSourcePosition.
• ES module declarations — import / export node classes.
• JSX / CSX — the csxToken lexer path + CSX codegen.
• Literate CoffeeScript (invertLiterate / isLiterate), shebang handling (checkShebangLine), baseFileName.

What's kept

The full CoffeeScript language: classes, inheritance and super, comprehensions and ranges, destructuring, splats, default parameters, string interpolation and heredocs, existential ?, switch, try/catch, do, the ** / %% operators, splice assignment, regexes, and the complete error-reporting path (pretty syntax errors) — so a typo still produces a clear message, not a crash. See test/corpus/ for the exercised subset.

Guarantee & verification

For the supported subset, compile(src, { bare: true }) is byte-for-byte identical to stock CoffeeScript 2.0.3. npm run verify (also npm test) compiles every file in test/corpus/ with both this fork and the stock 2.0.3 devDependency and asserts equal output.

The fork intentionally supports only the CoffeeScript that Fizzygum uses. Source that relies on a removed feature (JSX, import/export, source maps, literate) will not compile — that is by design, not a bug.

Re-deriving from source

This is a derivative of [email protected]'s compiled lib/coffeescript/*.js modules. The fork keeps only the compile-path modules, applies the edits in patched/ (each file documents its cut at the top), and bundles + minifies them into a single UMD:

npm install     # pulls [email protected] (devDep) + terser
npm run build   # writes dist/coffeescript.js (min) and dist/coffeescript.full.js
npm run verify  # asserts byte-identity vs stock 2.0.3 over test/corpus/

dist/ is committed so consumers need no build step; patched/ + build.js make the fork fully reproducible.

License / provenance

MIT. This is a derivative work of CoffeeScript (Copyright © 2009–2018 Jeremy Ashkenas and contributors, MIT). See LICENSE.