microsoft / microsoft/TypeScript

Update lib.dom.d.ts: `MutationObserverInit.attributeFilter` can accept an iterator

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#55,990 1 comment 1 reaction 2 assignees View on GitHub

@RyanCavanaugh is already working on this.

Since Sep 19, 2026.

  • #64332 by @copilot-swe-agent — open
Bug Domain: lib.d.ts Help Wanted Needs Human Review
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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:

Screenshot 2023-10-04 at 6 36 01 PM
Documentation Link

https://developer.mozilla.org/en-US/docs/Web/API/MutationObserver/observe#parameters

WIP Pull Request

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First steps

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  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Assessment

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