text: var outputFileSync = require("output-file-sync");
  var pathExists     = require("path-exists");
  var chokidar       = require("chokidar");
  var slash          = require("slash");
  var path           = require("path");
  var util           = require("./util");
  var fs             = require("fs");
  var _              = require("lodash");
  
  module.exports = function (commander, filenames) {
    function write(src, relative) {
      // remove extension and then append back on .js
      relative = relative.replace(/\.(\w*?)$/, "") + ".js";
  
      var dest = path.join(commander.outDir, relative);
  
      var data = util.compile(src, {
        sourceFileName: slash(path.relative(dest + "/..", src)),
        sourceMapTarget: path.basename(relative)
      });
      if (!commander.copyFiles && data.ignored) return;
  
      if (data.map && commander.sourceMaps && commander.sourceMaps !== "inline") {
        var mapLoc = dest + ".map";
        data.code = util.addSourceMappingUrl(data.code, mapLoc);
        outputFileSync(mapLoc, JSON.stringify(data.map));
      }
  
      outputFileSync(dest, data.code);
  
      util.log(src + " -> " + dest);
    }
  
    function handleFile(src, filename) {
      if (util.shouldIgnore(src)) return;
  
      if (util.canCompile(filename, commander.extensions)) {
        write(src, filename);
      } else if (commander.copyFiles) {
        outputFileSync(path.join(commander.outDir, filename), fs.readFileSync(src));
      }
    }
  
    function handle(filename) {
      if (!pathExists.sync(filename)) return;
  
      var stat = fs.statSync(filename);
  
      if (stat.isDirectory(filename)) {
        var dirname = filename;
  
        _.each(util.readdir(dirname), function (filename) {
          var src = path.join(dirname, filename);
          handleFile(src, filename);
        });
      } else {
        write(filename, filename);
      }
    }
  
    _.each(filenames, handle);
  
    if (commander.watch) {
      _.each(filenames, function (dirname) {
        var watcher = chokidar.watch(dirname, {
          persistent: true,
          ignoreInitial: true
        });
  
        _.each(["add", "change"], function (type) {
          watcher.on(type, function (filename) {
            var relative = path.relative(dirname, filename) || filename;
            try {
              handleFile(filename, relative);
            } catch (err) {
              console.error(err.stack);
            }
          });
        });
      });
    }
  };
  