How do diagnose battery life problems?

In recent releases of my app, I’ve noticed that when I leave the app backgrounded, it’s just eating up my battery. If I go to the iOS settings, it shows that my app is always eating a ton of battery.

What happens when an app is backgrounded? Do the setInterval calls still run? Do network requests from the app still run?

Is there any documentation on this anywhere? My understanding is that the app essentially freezes and all the intervals stop, etc.

I’m also doing background location, but that only gets used like 7 times a day so that most likely can’t be it.

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