ArrayBuffer to base64 encoded string

Question

I need an efficient (read native) way to convert an ArrayBuffer to a base64 string which needs to be used on a multipart post.

Answer 1

var blob = new Blob([arrayBuffer])

var reader = new FileReader();
reader.onload = function(event){
   var base64 =   event.target.result
};

reader.readAsDataURL(blob);