storage.html

<script>

function fill(cache) {
  let list = [];
  for (let i = 0; i < 30000; ++i) {
    list.push(cache.put('https://example.com/probably-crash-' + i, new Response('ok')))
  }
  return Promise.all(list);
}

function read(cache) {
  let start = performance.now();
  cache.keys().then(keys => {
    let end = performance.now();
    console.log(end - start);
  }).catch(e => {
    alert(e)
  })
}

function run () {
  caches.open("test").then(cache => {
    fill(cache).then(() => {
      read(cache);
    })
  })

}

</script>

<div>
Filling <span id="filled">...</span>
<button onclick="run()">Crash!</button>