Lockability for localForage.

Create a LockableForage instance with lkf = new LockableForage.LockableForage(localforage).

Lock with await lkf.lock(key, async () => { /* critical section */ });.

Trylock is also available: await lkf.tryLock(key, criticalSection);.

Inspired by but not based on https://github.com/elad/LockableStorage .

Timers

LockableForage is necessarily based on timers. It's impossible to guarantee removing a lock item before a browser window is closed, so the only way to be certain that locks don't hold forever is to make them time out.

By default, locks time out after one second, and are refreshed every 100ms. If your localforage backend driver is quite slow, it may make sense to change these timers.

You can change both timers with lkf.setTimes(x), where x is the refresh time, in milliseconds.

To change only the refresh timer or only the timeout timer, use lkf.setReacquisitionTime or lkf.setTimeoutTime.