Add lock by key

[gajus]

mutex library has a way to lock by key

https://www.npmjs.com/package/mutex#mutexlockstring-key-object-options-function-callback--lock

It is not clear how to implement equivalent strategy using this library.

[gajus]

Ended up developing https://github.com/gajus/mutual-exclusion

[DirtyHairy]

That's not a use case I have been using this package for so far, but you could do the same thing by keeping a map of locks, creating a new one if there is no existing lock, and removing it after release if ::isLocked() returns false.

I want to keep the actual Mutex and Semaphore classes as simple as possible, but I can add wrapper (similar to withTimeout) that hides this functionality behind the same interface, augmented with a key argument.

[gajus]

Well, my particular use case has been addressed by mutual-exclusion library, but maybe others will find it useful.