CoffeeScript vs js_of_ocaml

CoffeeScript is a language that compiles to JavaScript, so its output runs without a CoffeeScript interpreter. It can use existing JavaScript libraries, and JavaScript can use libraries written in CoffeeScript. Version 2 produces modern JavaScript syntax, including classes and arrow functions, and supports async functions and JSX. The `coffee` command runs scripts, compiles `.coffee` files to `.js`, and opens an interactive REPL; it can also generate inline or external source maps. Install it through npm, globally or as a project dependency. The core compiler can run in a browser or another JavaScript environment, while the command-line utility requires Node 6 or later. Its Node API compiles CoffeeScript strings and can return source maps or an abstract syntax tree. Babel transpilation is available when `@babel/core` is installed. The integrations section links to build tools, editors, frameworks, linters, formatters, and testing resources. JSX output always needs transpilation, and users must ensure their runtime supports the modern features they use or transpile the result. CoffeeScript is free and open source.

js_of_ocaml compiles OCaml bytecode programs into JavaScript for browsers and Node.js. It works with an existing OCaml installation and does not require libraries to be recompiled. Installation is available through opam, while Dune supports separate compilation in development and whole-program compilation in release builds. Whole-program compilation performs global dead-code elimination and cross-module optimization. The library provides a typed bridge between OCaml and JavaScript, including PPX syntax for properties, methods, constructors and objects. Browser bindings cover the DOM, Fetch, WebSockets, WebGL, workers and typed arrays. Optional packages add Lwt support, TyXML, JSON derivation and an OCaml toplevel in the browser. Documented targets include Node.js 18 or later, QuickJS-NG and modern ECMAScript 2020 browsers, including Chrome 80+, Firefox 74+, Safari 13.4+ and Edge 80+. Requirements include OCaml 4.13–5.5, Dune 3.20 or later and Menhir. The project is free and open source.