The internal implementation of the Upload widget allows you to identify which is the file object which is in the process of uploading to the remote endpoint.
Regardless of the mode of operation, the Upload generates a unique identifier (
uid) for each file. When the Upload is in a synchronous or asynchronous mode with its
batch option enabled, the single
uid that is generated stands for the whole batch of files which were selected at the same time. If the Upload is in an asynchronous mode with its
batch option disabled, the Upload generates a
uid for each separate file.
uid is added as a property of the
e.files collectio to all of the following events: