Memory leak: old results are not deleted from the cache

[juancampa]

Looking at the code it seems like old results are never removed from the cache, even when they reach their maxAge and become forever unused. I might be misreading it though.

[sindresorhus]

Even if you can't submit a fix, submitting a pull request with a failing test would be very helpful.

[greghawk]

@sindresorhus @keithamus Is there a fix for this? it is blowing out my servers memory at volume

[keithamus]

@greghawk for now you have to pass in your own Map as the {cache} option - and then using a timer of your own, empty the Map.

I'll add to this that I don't think this should be solved by mem alone. I think adding timeouts to mem would add too much internal state. I think the solution is perhaps to write a ttlMap style lib that complements this lib. (or of course, as the README suggests, you can use quick-lru)

[SamVerschueren]

I'm implementing it as we speak for expiry-map as it was reported as an issue over there as well.

Because I also need it for expiry-set, I'm looking in extracting the logic in a separate package. Still have some cleanup work to do and then actually extracting and releasing it as a package. But I believe it can easily be used by mem.

[SamVerschueren]

I implemented this in #19. Feel free to help testing and reviewing it.