How to strip type from Javascript FileReader base64 string?

Question

I\'ve got the following code in my Javascript:

var reader = new FileReader();
reader.onloadend = function () {
    alert(reader.result);
};

Answer 1

let reader: FileReader = new FileReader();

 reader.onloadend = (e) => {
    let base64String = reader.result.split(',').pop();
 };

or

let base64String = /,(.+)/.exec(reader.result)[1];