blob to dataurl, because I keep forgetting how to do it!

function.js

function blobToDataURL(blob) {
    return new Promise((fulfill, reject) => {
        let reader = new FileReader();
        reader.onerror = reject;
        reader.onload = (e) => fulfill(reader.result);
        reader.readAsDataURL(blob);
    })
}

Superb! Thanks.