Rotate base64 image (Javascript)

rotate.js

function rotate(srcBase64, degrees, callback) {
  const canvas = document.createElement('canvas');
  const ctx    = canvas.getContext('2d');
  const image  = new Image();

  image.onload = function () {
    canvas.width  = degrees % 180 === 0 ? image.width : image.height;
    canvas.height = degrees % 180 === 0 ? image.height : image.width;

    ctx.translate(canvas.width / 2, canvas.height / 2);
    ctx.rotate(degrees * Math.PI / 180);
    ctx.drawImage(image, image.width / -2, image.height / -2);

    callback(canvas.toDataURL());
  };

  image.src = srcBase64;
}

// Usage:
const img = document.getElementById('image');

rotate(img.attributes.src.value, 90, function(resultBase64) {
  img.setAttribute('src', resultBase64);
});