Web/API/MutationObserver/takeRecords

The MutationObserver method takeRecords() returns a list of all matching DOM changes that have been detected but not yet processed by the observer's callback function, leaving the mutation queue empty. The most common use case for this is to immediately fetch all pending mutation records immediately prior to disconnecting the observer, so that any pending mutations can be processed when stopping down the observer.

Syntax

const mutationRecords = mutationObserver.takeRecords()

Parameters

None.

Return value

An array MutationRecord objects, each describing one change applied to the observed portion of the document's DOM tree.

Note: The queue of mutations which have occurred, but not been delivered to the observer's callback is left empty after calling takeRecords().

Example

In this example, we demonstrate how to handle any undelivered MutationRecords by calling takeRecords() just before disconnecting the observer.

const targetNode = document.querySelector("#someElement");
const observerOptions = {
  childList: true,
  attributes: true
}

const observer = new MutationObserver(callback);
observer.observe(targetNode, observerOptions);

/* ...later, when it's time to stop observing... */

/* handle any still-pending mutations */

let mutations = observer.takeRecords();

observer.disconnect();

if (mutations) {
  callback(mutations);
}

The code in lines 12–17 fetches any unprocessed mutation records, then invokes the callback with the records so that they can be processed. This is done immediately prior to calling disconnect() to stop observing the DOM.

Specifications

Specification	Status	Comment
DOMThe definition of 'MutationObserver.takeRecords()' in that specification.	Living Standard

Browser compatibility

The compatibility table on this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request.

Update compatibility data on GitHub

	Desktop						Mobile
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet
takeRecords	Chrome Full support 18	Edge Full support 12	Firefox Full support 14	IE Full support 11	Opera Full support 15	Safari Full support 6	WebView Android Full support Yes	Chrome Android Full support 18	Firefox Android Full support 14	Opera Android Full support 14	Safari iOS Full support 6	Samsung Internet Android Full support 1.0

Legend

Full support  

Full support

MutationObserver.takeRecords() by Mozilla Contributors is licensed under CC-BY-SA 2.5.