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• I havesearched for related issues and found none that match my proposal.
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Relevant Package

typescript-estree

My proposal is suitable for this project

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Description

Continuing from#6404 (comment): we've been talking off-and-on for ages now about adding a thin layer of caching around TypeScript's type checking APIs.

do we want to do a weakmap memo on these? Eg

functionmemoize<TNode,TRet>(fn:(node:TNode)=>TRet):(node:TNode)=>TRet{constcache=newWeakMap<TNode,TRet>();return(node)=>{constcachedRet=cache.get(node);if(cachedRet){returncachedRet;}constnewRet=fn(node);cachedRet=cache.set(node,newRet);returnnewRet;};}

That would allow us to enforce that if two rules request the exact same node then we'll 100% use a fast path.

Doing a quick look at the implementation ofgetTypeAtLocation - it doesn't do any fast caching, so it does do a bunch of work.

IDK if this sort of thing would actually save any real time though - would be worth a test. Maybe we can file an issue to look at this later?

Additional Info

This'll require performance testing. Does it actually speed things up? Does it cause out-of-memory issues on our repo? Let's find out!

Strong candidate for including in thev6 betas. I'd like to get real world user testing to make sure this doesn't explode anybody.