Javascript Promises with FileReader()

Question

I have the following HTML Code:

And Here\'s my JS Code:

var inputFiles = document.getE         


        

Answer 1

Here is another modification to Jens' answer (piggybacking off Mido's answer) to additionally check the file size:

function readFileBase64(file, max_size){
        max_size_bytes = max_size * 1048576;
        return new Promise((resolve, reject) => {
            if (file.size > max_size_bytes) {
                console.log("file is too big at " + (file.size / 1048576) + "MB");
                reject("file exceeds max size of " + max_size + "MB");
            }
            else {
            var fr = new FileReader();  
            fr.onload = () => {
                data = fr.result;
                resolve(data)
            };
            fr.readAsDataURL(file);
            }
        });
    }