W3.org:

'A File object is a Blob object with a name attribute, which is a string;'

In case of File:

var d = new Date(2013, 12, 5, 16, 23, 45, 600);

var generatedFile = new File([Rough Draft ....], Draft1.txt, {type: 'text/plain', lastModified: d});



console.log(typeof generatedFile.name == 'string'); // true

In case of Blob:

var blob = new Blob();

console.log(typeof blob.name); // undefined

Condition:

var isFile = typeof FileOrBlob.name == 'string';