• Links

  • https://developer.mozilla.org/en-US/docs/Using_files_from_web_applications
  • https://medium.com/the-everyday-developer/detect-file-mime-type-using-magic-numbers-and-javascript-16bc513d4e1e
  • https://davidwalsh.name/file-api
  • https://davidwalsh.name/filereader

FileReader
  event handlers:
    onloadstart
		onprogress
		onloadend : failure or success
		onload : on success, (evt) => { evt.target.result is the data }
		onabort
		onerror
	methods
		abort
		readAsArrayBuffer : result will be ArrayBuffer
		readAsBinaryString : result will be binary data as string
		readAsDataURL : result will be data: URL
		readAsText : result will be content as string