const createImage = url =>
  new Promise((resolve, reject) => {
    const image = new Image();
    image.addEventListener('load', () => resolve(image));
    image.addEventListener('error', error => reject(error));
    image.setAttribute('crossOrigin', 'anonymous') ;// needed to avoid cross-origin issues on CodeSandbox
    image.src = url
  });

export async function getCroppedImg(imageSrc, pixelCrop) {
  const image = await createImage(imageSrc);
  const canvas = document.createElement('canvas');
  const ctx = canvas.getContext('2d');

  const maxSize = Math.max(image.width, image.height);
  const safeArea = 2 * ((maxSize / 2) * Math.sqrt(2));

  // set each dimensions to double largest dimension to allow for a safe area for the
  // image to rotate in without being clipped by canvas context
  canvas.width = safeArea;
  canvas.height = safeArea;

  // translate canvas context to a central location on image to allow rotating around the center.
  ctx.translate(safeArea / 2, safeArea / 2);
  ctx.translate(-safeArea / 2, -safeArea / 2);

  // draw rotated image and store data.
  ctx.drawImage(
    image,
    safeArea / 2 - image.width * 0.5,
    safeArea / 2 - image.height * 0.5
  );
  const data = ctx.getImageData(0, 0, safeArea, safeArea);

  // set canvas width to final desired crop size - this will clear existing context
  canvas.width = pixelCrop.width;
  canvas.height = pixelCrop.height;

  // paste generated rotate image with correct offsets for x,y crop values.
  ctx.putImageData(
    data,
    Math.round(0 - safeArea / 2 + image.width * 0.5 - pixelCrop.x),
    Math.round(0 - safeArea / 2 + image.height * 0.5 - pixelCrop.y)
  );

  // As Base64 string
  // return canvas.toDataURL('image/jpeg');

  // As a blob

  return new Promise(resolve => {
    canvas.toBlob(file => resolve(file))
  })
}