useMutations

useMutations(node, init?) returns a signal accessor that updates with each batch of MutationRecords observed on node. It is the reactive half of the pota/use/mutation emitter pair; for a plain callback use onMutations, and to attach an observer declaratively use mutated. The default init is { childList: true, subtree: true }.

Arguments

Argument	Type	Description
node	Node	Element to observe.
init	MutationObserverInit	Optional observer config; defaults to childList + subtree.

Returns: a signal accessor (reader function) holding the latest MutationRecord[] batch — undefined until the first batch arrives.

Examples

Read mutations reactively

Read the latest batch of records inside an effect; it re-runs whenever the node mutates. The accessor reads undefined until the first batch, hence the ?..

import { effect, render, signal } from 'pota'
import { useMutations } from 'pota/use/mutation'

function App() {
	const records = useMutations(document.body)
	const log = signal('mutations will appear here')

	effect(() => log.write(`mutations: ${records()?.length ?? 0}`))

	return <p>{log.read}</p>
}

render(App)