Dropzone.js + AWS S3 stalling queue - amazon-web-services

Question

I'm trying to impliment a dropzone.js uploader to amazon S3 using the aws-sdk.js for the browser. But when I exceed the 'parallelUploads' maximum in the settings, the queue never completes. I'm using the approach in the following link:
amazon upload
relevant parts of my code:
var dz = new Dropzone("#DZContainer", {
acceptedFiles: "image/*,.jpg,.jpeg,.png,.gif",
autoQueue: true,
autoProcessQueue: true,
parallelUploads: 10,
clickable: [".uploadButton"],
accept: function(file, done){
let params = {
"Bucket": "upload-bucket",
"Key": getFullKey(file.name),
Body: file,
Region: "us-east-1,
ContentType: file.type
}
file.s3upload = AWS.S3.ManagedUpload(params);
if (typeof(done) === 'function') done();
},
canceled: function(file) {
if (file.s3upload) file.s3upload.abort();
},
init: function () {
this.on('removedfile', function (file) {
if (file.s3upload) file.s3upload.abort();
});
}
)
dz.uploadFiles = function (files) {
for (var j = 0; j < files.length; j++) {
var file = files[j];
dz.SendFile(file);
}
};
dz.SendFile = function(file) {
file.s3upload.send(function (err, data) {
if (err) {
console.err(err)
dz.emit("error", file, err.message);
} else {
dz.emit("complete", file);
}
});
if I drag in (or use the clickable) more than 10 files, the first 10 complete but it never processes the rest of the queue. What am I missing? All help is appreciated
EDIT: With a little more digging into Dropzone, it looks as though the file status is never getting set to complete. I see a function called _finished() in the dropzone code, but I'm having a hard time figuring out what specifically is supposed to trigger that function. I have tried dz.emit("complete", file) listed below as well as adding dz.emit("success",file) but my breakpoint at the first line of the _finished() function never triggers. Thus the file.status never gets set to completed.
Does anyone know when/what/how _finished() is supposed to be run?

Answer 1

As mentioned in the edit, I was able to track down where the .status was not properly getting set. This seemed to be in a private Dropzone function called _finished()
With further examination, I noticed that _finished() seemed to also be calling emit("complete", file) after setting file.status to Dropzone.SUCCESS and also emitting "success". It then checks if autoProcessQueue is set and if it is, returns the result of a processQueue() call.
I had a hard time figuring out what triggered this function as it was on an onload event that eventually realized was tied to an XHTTPRequest object used by the internal uploader (which is being overridden by the S3 uploader)
So I modified the function to emulate what the Dropzone._finished() was doing and it's behaving as expected:
dz.SendFile = function(file) {
file.s3upload.send(function (err, data) {
if (err) {
console.err(err)
dz.emit("error", file, err.message);
} else {
file.status = Dropzone.SUCCESS;
dz.emit("success", file, data, err);
dz.emit("complete", file);
if(dz.options.autoProcessQueue)
dz.processQueue()
}
});