Function assertMatchesImage

test/matches-snapshot.ts:14–38

(actual: ImageDataLike, imageFilename: string)

};

export function assertMatchesImage(actual: ImageDataLike, imageFilename: string): void {
  if (!imageFilename.endsWith('.png')) {
    console.log('throwing');
    throw new Error('imageFilename must end in .png');
  }
  let fileBuffer;
  try {
    fileBuffer = fs.readFileSync(path.join(snapshotsPath, imageFilename));
  }
  catch (_) {
    writeImageSnapshot(actual, imageFilename);
    return;
  }
  const png = PNG.sync.read(fileBuffer);
  if (actual.data.length * 4 !== png.data.length) {
    throw new Error('Expected actual.length to match png.data.length');
  }
  const identical = actual.data.every((value, i) => value == png.data[i * 4]);
  if (!identical) {
    console.log(png.data);
    writeImageSnapshot(actual, imageFilename.replace('.png', '.error.png'));
    throw new Error('expected data to be identitcal');
  }

}

function writeImageSnapshot(actual: ImageDataLike, imageFilename: string) {
  const png = new PNG({