nodejs express fs iterating files into array or object failing

Question

So Im trying to use the nodejs express FS module to iterate a directory in my app, store each filename in an array, which I can pass to my express view and iterate through the l

Answer 1

I faced the same problem, and basing on answers given in this post I've solved it with Promises, that seem to be of perfect use in this situation:

router.get('/', (req, res) => {
  var viewBag = {}; // It's just my little habit from .NET MVC ;)

  var readFiles = new Promise((resolve, reject) => {
    fs.readdir('./myfiles/',(err,files) => {
      if(err) { 
        reject(err); 
      } else {
        resolve(files);
      }
    });
  });

  // showcase just in case you will need to implement more async operations before route will response
  var anotherPromise = new Promise((resolve, reject) => {
    doAsyncStuff((err, anotherResult) => {
      if(err) { 
        reject(err); 
      } else {
        resolve(anotherResult);
      }
    });
  });

  Promise.all([readFiles, anotherPromise]).then((values) => {
    viewBag.files = values[0];
    viewBag.otherStuff = values[1];
    console.log(viewBag.files); // logs e.g. [ 'file.txt' ]
    res.render('your_view', viewBag);
  }).catch((errors) => {
    res.render('your_view',{errors:errors}); // you can use 'errors' property to render errors in view or implement different error handling schema
  });
});

Note: you don't have to push found files into new array because you already get an array from fs.readdir()'c callback. According to node docs:

The callback gets two arguments (err, files) where files is an array of the names of the files in the directory excluding '.' and '..'.

I belive this is very elegant and handy solution, and most of all - it doesn't require you to bring in and handle new modules to your script.