How to create File object from Blob?

The File constructor (as well as the Blob constructor) takes an array of parts. A part doesn't have to be a DOMString. It can also be a Blob, File, or a typed array. You can easily build a File out of a Blob like this:

new File([blob], "filename")

This was the complete syntax which I had to use to convert a blob into a file, which I later had to save to a folder using my server.

var file = new File([blob], "my_image.png",{type:"image/png", lastModified:new Date().getTime()})