code: function use (filepath, destination) {
  	var startTime  = Date.now();
  	var text       = read(filepath);
  
  	if (text !== false) {
  		fs.writeFile(destination, jsx(text), function (err) {
  		    if (err) { throw err; }
  
  		    var endTime = Date.now();
  		    log('[Finished in ' + (endTime - startTime) + 'ms]');
  		}); 
  	} else {
  		log('no such file exits, ' + filepath);
  	}
  }
docs: use the file to transpile