window.requestIdleCallback type missing

[nstepien]

TypeScript Version: 4.1.0-dev.20200925

Search Terms: requestIdleCallback

Code

requestIdleCallback(() => {})

Expected behavior:
requestIdleCallback is typed.

Actual behavior:

Cannot find name 'requestIdleCallback'. ts(2304)

Playground Link:
https://www.typescriptlang.org/play?#code/E4UwjgriDOAuCSATANiAwgQ2cgRhgxgNYAUxAlAAQC8AfBQN4C+ZQA

Related Issues:
#21309
The previous issue was labelled as "working as intended" over 2 years ago, but I don't think the API is experimental anymore. It is available in Chrome/Firefox/Edgium, and Safari (behind a flag).
https://www.w3.org/TR/requestidlecallback/
https://w3c.github.io/requestidlecallback/
https://caniuse.com/requestidlecallback
https://developer.mozilla.org/en-US/docs/Web/API/Window/requestIdleCallback

[utsav0209]

Do we want the support for this?

As I read from MDN safari still does not support the requestIdleCallback.

If we want to have support, I can make a PR.

[RyanCavanaugh]

I want to discuss our experimental API coverage in lib.d.ts before committing to accepting a PR, but certainly it should eventually be in there

[thw0rted]

Ryan, on the previous issue you said that TS doesn't support experimental APIs. The MDN page for requestIdleCallback is marked as experimental but so is fetch -- the biggest difference I can see is that requestIdleCallback comes from a "Proposed Recommendation", rather than a "Living Standard". Is the status of the spec the issue here?

(It strikes me as strange that requestIdleCallback doesn't appear to have gone anywhere in over 3 years, but is supported in all modern browsers except Safari. I guess the old draft didn't have any major problems so they've left it alone?)

[nstepien]

microsoft/TypeScript-DOM-lib-generator#1029
It's in TS 4.4! Thank you