mason/lib/builders/javascript.js

simple, fun, static-file builder for jade, stylus, and javascript

var util = require('../util');
var jsp = require("uglify-js").parser;
var pro = require("uglify-js").uglify;

module.exports = function(options) {
  var asset = options.asset;

  // Build lists of source and destination files
  var sourceFiles = util.buildPaths(options.dir, asset.fromBase, asset.fromSrc);
  var destFiles = util.buildPaths(options.dir, asset.toBase, asset.toSrc);

  // Concatenate and compress the files
  var code = util.concatFiles(sourceFiles);
  var compressed = compressJS(code);

  // Write the destination files
  return destFiles.forEach(writeCompressed);

  function writeCompressed(destFile) {
    util.writeFile(destFile, compressed);
  }
};

function compressJS(code) {
  // parse the JS code into AST
  var ast = jsp.parse(code);
  // mangle names
  ast = pro.ast_mangle(ast);
  // compress
  ast = pro.ast_squeeze(ast);
  // generate JS from the compressed AST
  return pro.gen_code(ast);
}