Closure Compiler is a JavaScript optimizing compiler. It parses your JavaScript, analyzes it, removes dead code and rewrites and minimizes what's left. It also checks syntax, variable references, and types, and warns about common JavaScript pitfalls. It is used in many of Google's JavaScript apps, including Gmail, Google Web Search, Google Maps, and Google Docs.

ClojureScript compiler and core runtime library.

The Maven Wisdom Plugin allows building applications for Wisdom.

Joo Compiler

Minium Web Elements

Twibs: Utilities

This plugin compiles Jangaroo sources to JavaScript.

Maven plugin for compressing JS files at build time