Free resources (free detached nodes from memory)

[MosheZemah]

Found an issue when using virtualized list (https://github.com/bvaughn/react-virtualized), where unmounted react components (connected to store using connect) were not collected by the garbage collector.
I'm not sure what is the exact explanation here, but it solved my problem.

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[markerikson]

Can you put together a sandbox that shows the problem in action, so that we can check to see if this actually makes any difference?

I don't see any reason why this change would be a problem, I just want to see how much it helps.

[MosheZemah]

Can you put together a sandbox that shows the problem in action, so that we can check to see if this actually makes any difference?

I don't see any reason why this change would be a problem, I just want to see how much it helps.

Hi, thanks for replying.
It seems like a specific case with virtualized list, where I scroll up and down and many components are mounting and unmounting (every time they enter/exit the DOM). I'm not sure I'll be able to reproduce it on a sandbox. Is there any possibility that "onStateChange" which holds reference to checkForUpdates somehow retain a reference to the component which keeps it from being garbage collected? I can add a screenshot where I have allot of Detached div elements, and I've traced them down to their holder - "Subscription" (forcing GC didn't free them). After applying my change, the problem seems to be solved.

[markerikson]

Well, connect is now a function component, so there's no component reference that can be accessed by app logic.

In theory, what I would expect is:

• React unmounts the component and cleans up the hooks list
• No hooks point to the Subscription instance, so it's GC'd
• Anything the Subscription points to is GC'd

But, all that said, I see no reason why this change would be an issue, so let's get it in.