less-watch

#!/usr/bin/env /usr/local/bin/node
var fs = require('fs'),
  path = require('path'),
  child_process = require('child_process'),
  glob = require('glob'),
  winston = require('winston'),
  watched_filepaths = [],
  config_path = path.join(process.env.HOME, '.less-watch'),
  logfile = path.join(process.env.HOME, 'Library', 'Logs', 'less-watch.log')
  logger = new (winston.Logger)({
    transports: [
      new (winston.transports.Console)(),
      new (winston.transports.File)({ filename: logfile })
    ]
  });

function reload() {
  logger.info(watched_filepaths.length ? "Reloading" : "Loading");
  watched_filepaths.forEach(function(filepath) {
    fs.unwatchFile(filepath);
  });
  watched_filepaths = [];

  // "restart" is a special action keyword
  watch(config_path, 'restart');
  fs.readFile(config_path, 'utf8', function (err, data) {
    if (err) throw err;
    data.split(/\n+/g).forEach(function(line) {
      var parts = line.split(/\s*:\s*/g);
      if (parts[0] && parts[1])
        watch(parts[0], parts[1]);
    });
  });
}

function watch(globpath, action) {
  glob(globpath, function(err, filepaths) {
    // for single files, filepaths will just be one file: the exact match
    filepaths.forEach(function(filepath) {
      // for each file, decide on its command
      var ext = filepath.match(/(\.\w+)?$/)[1],
        command = action.
        replace(/\{file\}/g, filepath).
        replace(/\{basename\}/g, path.basename(filepath, ext)).
        replace(/\{dirname\}/g, path.dirname(filepath));
      // save the filepath so that we can unwatch it easily when reloading, and start the watch
      watched_filepaths.push(filepath);
      fs.watchFile(filepath, {interval: 250}, function(curr, prev) {
        // ignore simple accesses
        if (curr.mtime.valueOf() != prev.mtime.valueOf() || curr.ctime.valueOf() != prev.ctime.valueOf()) {
          if (command === 'restart') {
            reload();
          }
          else {
            logger.warn('> ' + filepath + ' changed.');
            logger.warn('$ ' + command);
            child_process.exec(command, function (error, stdout, stderr) {
              logger.info('stdout: ' + stdout);
              logger.info('stderr: ' + stderr);
              if (error !== null) {
                logger.error('exec error: ' + error);
              }
            });
          }
        }
      });
    });
  });
}

reload();