Make updateState available in constructor instead of componentDidMount

[GerritSe]

Hey there. We recently started using react-copy-write in a small application and had a great experience so far, but there is still something that interferes with our application flow, which is the inability to call mutate before a provider is fully mounted.

https://codesandbox.io/s/oowloz2qk9

In this example the app will crash, because mutate is called before the surrounding provider is fully mounted. We want our ApiProvider to be wrapped around the whole app while still being able to use life cycle hooks to do initialization work that could mutate the state this provider gives us.

What we did for experimental reasons is to move the componentDidMount code from CopyOnWriteStoreProvider to a constructor and everything worked fine afterwards. So my question is whether it's possible to do this switch or if there are special reasons for the design decision to make updateState only available after componentDidMount of CopyOnWriteStoreProvider ran? Are there any performance implications or other pitfalls we are overlooking? If not I'd be glad to open a PR for this issue.

[kafein]

@aweary Same question, is it possible to move componentDidMount code in to constructor? Don't want to use setTimeout(() => { mutate(...) }, 0)

[kafein]

@aweary Sorry to rush. I need to make a decision quickly to use this library or not. Is it possible to make this happen?

[aweary]

@kafein I'm not going to be doing anything else with this library until React Conf this month. If you can I'd recommend you wait until then.

[kafein]

@aweary Thanks for reply. I'll wait.

[aweary]

Alright, coming back to this I think moving it to constructor would be mostly fine. The issue is that the constructor may be called without the component ever being mounted (like with Suspense), so it's possible to get in a weird state where updateState is referring to a component that didn't mount.

[kafein]

Hi @aweary
Thanks for explanation. I see the point, you are right. Instead of throwing error on mutate function, we can queue requests then in provider cdm lifecycle we can dequeue and call the requests. Is this reasonable?

Not sure about test but i made a pr. #61