javascript convert image to base64

1function getBase64Image(src, callback, outputFormat) {
2      const img = new Image();
3      img.crossOrigin = 'Anonymous';
4      img.onload = () => {
5        const canvas = document.createElement('canvas');
6        const ctx = canvas.getContext('2d');
7        let dataURL;
8        canvas.height = img.naturalHeight;
9        canvas.width = img.naturalWidth;
10        ctx.drawImage(img, 0, 0);
11        dataURL = canvas.toDataURL(outputFormat);
12        callback(dataURL);
13      };
14
15      img.src = src;
16      if (img.complete || img.complete === undefined) {
17        img.src = "data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///ywAAAAAAQABAAACAUwAOw==";
18        img.src = src;
19      }
20    }

1function getBase64Image(img) {
2  var canvas = document.createElement("canvas");
3  canvas.width = img.width;
4  canvas.height = img.height;
5  var ctx = canvas.getContext("2d");
6  ctx.drawImage(img, 0, 0);
7  var dataURL = canvas.toDataURL("image/png");
8  return dataURL.replace(/^data:image\/(png|jpg);base64,/, "");
9}
10
11var base64 = getBase64Image(document.getElementById("imageid"));
12

1function encodeImageFileAsURL(element) {
2  var file = element.files[0];
3  var reader = new FileReader();
4  reader.onloadend = function() {
5    console.log('RESULT', reader.result)
6  }
7  reader.readAsDataURL(file);
8}
9<input type="file" onchange="encodeImageFileAsURL(this)" />

1function toDataURL(url, callback) {
2  var xhr = new XMLHttpRequest();
3  xhr.onload = function() {
4    var reader = new FileReader();
5    reader.onloadend = function() {
6      callback(reader.result);
7    }
8    reader.readAsDataURL(xhr.response);
9  };
10  xhr.open('GET', url);
11  xhr.responseType = 'blob';
12  xhr.send();
13}
14
15toDataURL('https://cdn.discordapp.com/attachments/571092147801948204/784586541146177606/6f32c864-985a-481d-8d8e-bd1f14ab9951.png', function(dataUrl) {
16  console.log('RESULT:', dataUrl)
17})