doc: add snippet for AsyncResource and EE integration

[puzpuzpuz]

Continuation of #33736

Adds a snippet for AsyncResource + EventEmitter integration, based on asyncResource.runInAsyncScope.bind.

Checklist

• make -j4 test (UNIX), or vcbuild test (Windows) passes
• documentation is changed or added
• commit message follows commit guidelines

[jasnell]

It may be worthwhile building this in the the EventEmitter API (and possibly the EventTarget API). We've talked before about adding a context type of option to events, which could be expressed as an additional argument to addListener/on/once ... e.g.

constasyncResource=newAsyncResource('request');req.on('close',()=>{},asyncResource)

Under the covers it would effectively just do exactly what this example does, but in a way that is a bit more ergonomic for the user. For instance, in order to subsequently remove the event listener, the user has to track the bound function themselves (e.g. const fn = asyncResource.runInAsyncScope.bind(asyncResource, () => {}); ee.on('foo', fn'); ee.off('foo', fn); which is a bit cumbersome when we could handle it internally in a way similar to how we approach once handlers.

For now, however, this example is very valuable.

[Qard]

For what it's worth, I still think having an actual method for this is friendlier, and it's simple enough that the maintenance burden is near zero.

bindToAsyncScope(fn,thisArg){returnthis.runInAsyncScope.bind(this,fn,thisArg);}

I'm +0 on this. If this is how we want to proceed, that's fine. 🤷

[puzpuzpuz]

@Qard optimistically, this doc addition is a temp measure while EEs/streams used in the core are not integrated properly with async_hooks (see #33723). Once they're integrated (hopefully, this is going to happen), it's easy to remove this addition.

[nodejs-github-bot]

CI: https://ci.nodejs.org/job/node-test-pull-request/31760/

[nodejs-github-bot]

CI: https://ci.nodejs.org/job/node-test-pull-request/31762/

[nodejs-github-bot]

CI: https://ci.nodejs.org/job/node-test-pull-request/31764/

[Qard]

Yep, my perspective was just due to the other issue being closed before so it seemed like we decided against that route in favour of only documenting it. I would still like to work towards an actual fix in core. Since it seems the doc change is being considered more as a potentially temporary solution, I'll upgrade to 👍 .

[nodejs-github-bot]

CI: https://ci.nodejs.org/job/node-test-pull-request/31792/

[nodejs-github-bot]

CI: https://ci.nodejs.org/job/node-test-pull-request/31821/

[nodejs-github-bot]

CI: https://ci.nodejs.org/job/node-test-pull-request/31827/

[puzpuzpuz]

Landed in db3d6b3