javascript callbacks

gistfile1.js

// this first version uses a function callback to pass in the object reference... 

for (var i = 0; i < files.length; i++) {                       // WORKS
   var setFile = function(file) {                                               
      return function(err, data) {
         if (err) throw err;
         file[1] = data;
      };
   };
   fs.readFile(files[i][2], 'utf8', setFile(files[i]));
}

// compared with

for (var i = 0; i < files.length; i++) {                        // DOESN'T WORK
   fs.readFile(files[i][2], 'utf8', function(err, data) {
      if (err) throw err;
      file[i][1] = data;
   });
}