Google Web Toolkit - Development toolkit for building and optimizing browser-based applications. Its goal is to enable productive development of high-performance web applications without the developer having to be an expert in browser quirks, XMLHttpRequest, and JavaScript. jashkenas/coffee-script Wiki - List of languages that compile to JavaScript. Grunt - Automation, performing repetitive tasks like minification, compilation, unit testing and linting. gulp.js - Build system automating tasks: minification and copying of all JavaScript files, static images, capable of watching files to automatically rerun the task when a file changes. fusioncharts/jslink - Automated module concatenation with dependency management. volo - Tool for creating web projects, adding dependencies and automating tasks. DcodeIO/Preprocessor.js - Provides a JavaScript source file preprocessor for building different versions of a library. Compatible with CommonJS, RequireJS/AMD, Sim, node.js and Closure compiler. DcodeIO/MetaScript - Tool for build time meta programming using JavaScript as the meta language. Written between the lines it enables developers to transform sources in every way possible. Brunch - Compiles scripts, templates, styles. Features linting, concatenation, generates source maps, copies assets, static files and monitor file for changes. fat/smoosh - Tool for packaging CSS and JavaScript projects. clojure/clojurescript - Compiler for Clojure that targets JavaScript. Jangaroo - Project building developer tools that adopt ActionScript 3 to create JavaScript frameworks and applications. Dart - Platform for scalable web app engineering that compiles to JavaScript. Js2coffee - Helps migrate projects to CoffeeScript by compiling JavaScript code into CoffeeScript. Also available as a NodeJS module.