perf_hooks: expose `performance` global

[silverwind]

Browsers export a performance global, and I think we should too if the perf_hooks module is stable enough (and can be lifted from experimental stability) to allow easy usage in isomorphic scripts.

[juanarbol]

I'm quite confused, it would be something like performance.perfMember, where perfMember is provided by an abstraction layer of perf_hook module?

[Trott]

I'm quite confused, it would be something like performance.perfMember, where perfMember is provided by an abstraction layer of perf_hook module?

I think the suggestion is that perf_hooks.performance should be exposed as global.performance.

[juanarbol]

In that case won't be difference between using require like: const { performance } = require('perf_hooks'), and just using global such as global.performance? A package that behaves like a module and is part of global, feels weird to me (IMO)

[Trott]

In that case won't be difference between using require like: const { performance } = require('perf_hooks'), and just using global such as global.performance? A package that behaves like a module and is part of global, feels weird to me (IMO)

console.log(require('timers').setTimeout === global.setTimeout); // true

[juanarbol]

can I work on this?

[silverwind]

@jasnell any objections here?

[juanarbol]

Can I?

[Trott]

Can I?

Yes. Not that you need my permission or authority or anything, but if it makes you feel OK about forging ahead: Go for it. No guarantees that it will be accepted or that someone else isn't already working on it (although they probably aren't), but if this is something you'd like to see in Node.js core, you should totally put together a pull request for it.

[juanarbol]

Done at #29432 using perf_hooks module

[jasnell]

Yikes, I just spotted this. There's a reason we don't expose it as a global... Specifically, doing so is semver-major and the current implementation is not fully compatible with the browser version.

[joyeecheung]

IIRC, the convention is exposing a Web API to global when it is no longer experimental. I think at least we should take a look into the criteria for moving performance out of experimental status first.