Another trick most people don’t realize is that not only is the fetch api is asynchronous but response.json() does the conversion in a background thread and is non UI blocking.

If you have a large json object. You can use the fetch api to work with it. If you need to cache it, use the cache storage api. Unlike localStorage which will freeze the UI, cache storage wont.

It’s slightly slower since it needs to talk to another thread but who cares as long as the UI is responsive to do other things.