Internet Explorer toDataURL()替代？

function getDataURLForIE(img) {
  const canvas = document.createElement("canvas");
  const ctx = canvas.getContext("2d");
  canvas.width = img.width;
  canvas.height = img.height;
  ctx.drawImage(img, 0, 0);

  return new Promise((resolve, reject) => {
    canvas.toBlob((blob) => {
      if (!blob) {
        reject(new Error("Could not convert image to blob"));
        return;
      }
      const reader = new FileReader();
      reader.readAsDataURL(blob);
      reader.onloadend = () => {
        resolve(reader.result);
      };
    });
  });
}