useRef for creation of objects?

[vikr01]

I've been seeing a common pattern of creating an object that is an instance of a class in a useRef call:

const mapRef = useRef(new Map());

Can we maybe come up with a version of useRef that works a bit similarly to useMemo, but that it only executes the function the first time?:

const mapRef = useCreationRef(()=>new Map());

Looking at this comparatively on jsperf, it seems quite clear that the second version would always be faster when it involves creation of class objects. Especially when considering custom class objects, which could have constructors that do a lot more than just initialization.

If it's welcome, I'm happy to put up a PR for this.

[theKashey]

why you could not store data in the state?
why you could not transfer data from the state?

 useRef(useState(() => new Map())[0]);

[vikr01]

why you could not store data in the state?
why you could not transfer data from the state?

 useRef(useState(() => new Map())[0]);

I didn't say I did it, so I'm not sure why you're asking me. There's a ton of cases I'm seeing like this at Facebook.

Looks like Dan already gave an answer like this on a similar thread facebook/react#14490 (comment).