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 MutationRecord
s 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 |
---|---|---|
DOM The definition of 'MutationObserver.takeRecords()' in that specification. |
Living Standard |
Browser compatibility
Desktop | Mobile | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
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