ng-file-upload sequential promises - angularjs

Question

With this directive: ng-file-upload
How can I upload sequentially (in order, queue) multiple files one by one? I'm thinking about chained promises, but I don't know how can I combine promises and directive.
This is an example to upload multiple files, but all at the same time and not in order.
This is my code:
for (var i = 0; i < files.length; i++) {
Upload.upload({
url: config.base+'/upload/',
data: {
file: files[i],
}
}).then(function (response) {
vm.reloadImatges();
vm.upload.progress=0;
vm.upload.files--;
}, function (resp) {
}, function (evt) {
vm.upload.progress = parseInt(100.0 * evt.loaded / evt.total);
});
}

Answer 1

I found a solution, maybe not the best, but it works
http://jsfiddle.net/erLax2fm/2/
Code below:
var doSomething = function (index) {
var defer = $q.defer();
Upload.upload({
url: url: config.base+'/upload/',
data: {
file: objects[index]
}
}).then(function (response) {
objects[index].processed = true;
if (objects[++index]) {
defer.resolve(index);
} else {
defer.reject();
}
}, function (response) {
}, function (evt) {
vm.upload.progress = parseInt(100.0 * evt.loaded / evt.total);
});
defer.promise.then(doSomething);
};
doSomething(0);