update-fixtures.mjs

import { thumbnailFixtures } from "./fixtures.mjs";
import fetch from 'node-fetch';
import { mkdir, writeFile } from 'node:fs/promises';
import * as path from 'node:path';

async function main() {
  await mkdir(path.join('./fixtures', 'thumbnails'), { recursive: true });
  const promises = [];

  for (const fixture of thumbnailFixtures) {

    promises.push((async () => {
      const text = await (await fetch(fixture.url)).text();
      await writeFile(path.join('./fixtures', 'thumbnails', `${fixture.label}.json`), text);
    })())
    //
  }

  await Promise.all(promises);
}

main().then(() => {
  console.log('Done!');
});