Add types for window.performance.getEntriesByType

[third774]

Search Terms

getEntriesByType
PerformanceMark
PerformanceMeasure
PerformanceResourceTiming

Suggestion

Add types for the getEntriesByType API

I found this old issue (Jul 5, 2018) and saw that experimental API's are not included in lib.dom.d.ts. The following API's don't appear to have experimental warnings on them on the MDN docs. Hopefully this means these are no longer experimental and types can be added now?

https://developer.mozilla.org/en-US/docs/Web/API/PerformanceMark
https://developer.mozilla.org/en-US/docs/Web/API/PerformanceMeasure
https://developer.mozilla.org/en-US/docs/Web/API/PerformanceResourceTiming

Use Cases

Getting specific strongly typed information for the entries when accessed via this API.

Examples

// resources would be of type PerformanceResourceTiming[]
const resources = window.navigation.getEntriesByType("resource");

// resources would be of type PerformanceMeasure[]
const measures = window.navigation.getEntriesByType("measure");

// marks would be of type PerformanceMark[]
const marks = window.navigation.getEntriesByType("mark");

// paints would still be of type PerformanceEntryList
const paints = window.navigation.getEntriesByType("paint");

Checklist

My suggestion meets these guidelines (not sure about the first one):

• This wouldn't be a breaking change in existing TypeScript/JavaScript code
• This wouldn't change the runtime behavior of existing JavaScript code
• This could be implemented without emitting different JS based on the types of the expressions
• This isn't a runtime feature (e.g. library functionality, non-ECMAScript syntax with JavaScript output, etc.)
• This feature would agree with the rest of TypeScript's Design Goals.

[third774]

Doh! Tried to open a PR for this, but looks like the work is over in https://github.com/Microsoft/TSJS-lib-generator. Should I move this issue to that repo?

[TaylorPzreal]

Waiting the feature.

[DerGernTod]

any updates on this?

[HolgerJeromin]

This is fixed since a few versions. Probably 4.4 or even earlier.
microsoft/TypeScript-DOM-lib-generator#1094 (comment)

[billyvg]

@HolgerJeromin That is a different issue that doesn't address the return type of getEntriesByType(), see https://www.typescriptlang.org/play?ssl=14&ssc=1&pln=14&pc=61#code/PTAEAUFMCcDMHtoFsCGA7AxpAcigbgJYDmKALgfGgCoFIFpEDaAugFAaUDOpoa+xZCmgCiaUtAKROoALygA7vQAm8eQDoADjATJ0WNUUilR4yZwBCATyqWtACgDkfQiXKUHASgDcrViAjaiKiYkABKUvAArtBYNHQMLOxcPNAR0VjScopoKupacEF6kAZGJhJSVjb2AESpnFExkNXevv5QBbohALKQKJzRkIkcaNygSL39dbIKyqqagZ36hsZi5RbWtpB21eN9A80+fmDtOsFYXSjQANZDyWOXV5kzOXP5p0UlK6YVGzWo1wdWscFmdIOAUPRSHF6EQkiMeBoIWIntlcvMOqDPmUzJVNttEZCDkA

[HolgerJeromin]

Ok, missed that detail. Current state models spec:
https://w3c.github.io/performance-timeline/#extensions-to-the-performance-interface

But yes could be more clear by adding overridingTypes:
https://github.com/microsoft/TypeScript-DOM-lib-generator#when-the-type-exists-but-is-wrong

BTW, added type debug information to your playground link.

[schickling]

Is someone aware of any available NPM package that provides the missing types as a workaround for now?

[RyanCavanaugh]

Confirmed on 5.9, the requested specialization is still not there.

It'd be great if OP's code example were correct (it's .performance not .navigator) and clarified the current behavior

[DerGernTod]

If this is going to be worked on, I'd like to highlight that this also applies to performance.getEntriesByName - it supports a second argument specifying the type: https://developer.mozilla.org/en-US/docs/Web/API/Performance/getEntriesByName

I think it makes sense to type these function return types depending on the second argument, so that if I call e.g. performance.getEntriesByName("myMark", "mark"), I properly get a PerformanceMark.