Convert an image url to a base64 data URL

image_url_to_base64.js

 this.toDataURL(this.data.photoUrl, (dataUrl) => {
     console.log(dataUrl);
  })


  toDataURL(url, callback) {
    var xhr = new XMLHttpRequest();
    xhr.onload = function() {
      var reader = new FileReader();
      reader.onloadend = function() {
        callback(reader.result);
      }
      reader.readAsDataURL(xhr.response);
    };
    xhr.open('GET', url);
    xhr.responseType = 'blob';
    xhr.send();
  }