State Persistence (localStorage)

(function() {
 var uploader = new MultipleUpload('#demo', {
 uploadUrl: '/api/upload',
 multiple: true,
 persistState: true,
 persistKey: 'demo-persist'
 });
 document.getElementById('clear-state').addEventListener('click', function() {
 uploader.clearPersistedState();
 uploader.reset();
 });
 document.getElementById('reload-btn').addEventListener('click', function() {
 location.reload();
 });
})();

Surviving a reload

persistState defaults to false. Turned on, in-flight uploads are written to storage so a reload, a crash or a closed tab does not lose the queue. persistAdapter defaults to 'localStorage'; IndexedDB is the other option and the one to choose when you also want the file bytes kept.

What survives depends on the adapter

localStorage can hold the queue's bookkeeping — which files, how far each got — but not the File objects themselves, so the user has to re-pick the files before the resume continues. IndexedDB can store the blobs too, which is what makes resume genuinely zero-click. That is the whole difference between the two, and it is worth deciding deliberately.