c13.js

// image as dataURL
let jpeg = canvas.toDataURL('image/jpg'); // 0.92
let webp = canvas.toDataURL('image/webp', 0.5);
//zip 
let jsZip = new JSZip();
let folder = jsZip.folder("images");
let baseString = getBase64String(jpeg);
folder.file("image1.jpeg", baseString, {base64 : true});
let baseString2 = getBase64String(webp);
folder.file("image2.webp", baseString2, {base64 : true});
Generate the zip file
zip.generateAsync({type:"blob"}).then(function (content) {
      content = URL.createObjectURL(content);
      let name = `JSJeep.zip`;
      download(content, name); // already written above
});