dropzone.js - how to do something after ALL files are uploaded

EDIT: There is now a queuecomplete event that you can use for exactly that purpose.

Previous answer:

Paul B.'s answer works, but an easier way to do so, is by checking if there are still files in the queue or uploading whenever a file completes. This way you don't have to keep track of the files yourself:

Dropzone.options.filedrop = {
  init: function () {
    this.on("complete", function (file) {
      if (this.getUploadingFiles().length === 0 && this.getQueuedFiles().length === 0) {
        doSomething();
      }
    });
  }
};

Just use queuecomplete that's what its there for and its so so simple. Check the docs http://www.dropzonejs.com/

queuecomplete > Called when all files in the queue finished uploading.

      this.on("queuecomplete", function (file) {
          alert("All files have uploaded ");
      });

There is probably a way (or three) to do this... however, I see one issue with your goal: how do you know when all the files have been uploaded? To rephrase in a way that makes more sense... how do you know what "all" means? According to the documentation, init gets called at the initialization of the Dropzone itself, and then you set up the complete event handler to do something when each file that's uploaded is complete. But, what mechanism is the user given to allow the program to know when he's dropped all the files he's intended to drop? If you are assuming that he/she will do a batch drop (i.e., drop onto the Dropzone 2-whatever number of files, at once, in one drop action), then the following code could/possibly should work:

Dropzone.options.filedrop = {
    maxFilesize: 4096,
    init: function () {
        var totalFiles = 0,
            completeFiles = 0;
        this.on("addedfile", function (file) {
            totalFiles += 1;
        });
        this.on("removed file", function (file) {
            totalFiles -= 1;
        });
        this.on("complete", function (file) {
            completeFiles += 1;
            if (completeFiles === totalFiles) {
                doSomething();
            }
        });
    }
};

Basically, you watch any time someone adds/removes files from the Dropzone, and keep a count in closure variables. Then, when each file download is complete, you increment the completeFiles progress counter var, and see if it now equals the totalCount you'd been watching and updating as the user placed things in the Dropzone. (Note: never used the plug-in/JS lib., so this is best guess as to what you could do to get what you want.)

A 'queuecomplete' event has been added. See Issue 317.

this.on("totaluploadprogress", function(totalBytes, totalBytesSent){


                    if(totalBytes == 100) {

                        //all done! call func here
                    }
                });