Check if variable holds File or Blob
Easiest way:
a = new File([1,2,3], "file.txt");b = new Blob([1,2,3]);c = "something else entirely";a instanceof File> trueb instanceof File> falsec instanceof File> false
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'); // trueIn case of Blob:
var blob = new Blob();console.log(typeof blob.name); // undefinedCondition:
var isFile = typeof FileOrBlob.name == 'string';
One liner solution to make life easier.
Based on Ric Flair
const isFile = input => 'File' in window && input instanceof File;const isBlob = input => 'Blob' in window && input instanceof Blob;const a = new File([1,2,3], "foo.txt", {type: "text/plain"});...console.log(isFile(a)) // true...