Repository navigation
Update lib.dom.d.ts: MutationObserverInit.attributeFilter can accept an iterator #55990
Description
⚙ Compilation target
n/a
⚙ Library
lib.dom
Missing / Incorrect Definition
MutationObserverInit
Sample Code
The following code works in Chredge, Firefox, and Safari:
const obs = new MutationObserver((records) => {
console.log(...records)
})
const s = new Set(['foo', 'bar'])
obs.observe(document.body, {
attributeFilter: s.keys() // <--------- HERE
})
document.body.setAttribute('foo', 'foo')
document.body.removeAttribute('foo')
document.body.setAttribute('bar', 'bar')
document.body.removeAttribute('bar')Edge screenshot:
Documentation Link
https://developer.mozilla.org/en-US/docs/Web/API/MutationObserver/observe#parameters
Activity
RyanCavanaugh commentedon Sep 19, 2026
MutationObserverInit.attributeFilteris currently declared asstring[], but the platform accepts an iterable of strings. In Edge 153.0.4234.32,Set<string>.keys()is accepted and filters both requested attributes. TypeScript 5.2.2 and current native 7.1.0-dev.20260918.1 both report TS2740 because the iterator is not assignable tostring[].This concise code demonstrates the mismatch:
The DOM specification defines
attributeFilteras a sequence of DOM strings, whose Web IDL conversion accepts iterables. The declaration should model that accepted iterable input.