PerformanceLongAnimationFrameTiming: toJSON() method

Limited availability

This feature is not Baseline because it does not work in some of the most widely-used browsers.

Experimental: This is an experimental technology
Check the Browser compatibility table carefully before using this in production.

The toJSON() method of the PerformanceLongAnimationFrameTiming interface is a serializer; it returns a JSON representation of the PerformanceLongAnimationFrameTiming object.

Syntax

js
toJSON()

Parameters

None.

Return value

A JSON object that is the serialization of the PerformanceLongAnimationFrameTiming object.

Examples

Using the toJSON method

In this example, calling entry.toJSON() returns a JSON representation of the PerformanceLongAnimationFrameTiming object.

js
const observer = new PerformanceObserver((list) => {
  list.getEntries().forEach((entry) => {
    console.log(entry.toJSON());
  });
});

observer.observe({ type: "long-animation-frame", buffered: true });

This would log a JSON object like so:

json
{
  "blockingDuration": 0,
  "duration": 60,
  "entryType": "long-animation-frame",
  "firstUIEventTimestamp": 11801.099999999627,
  "name": "long-animation-frame",
  "renderStart": 11858.800000000745,
  "scripts": [
    {
      "duration": 45,
      "entryType": "script",
      "executionStart": 11803.199999999255,
      "forcedStyleAndLayoutDuration": 0,
      "invoker": "DOMWindow.onclick",
      "invokerType": "event-listener",
      "name": "script",
      "pauseDuration": 0,
      "sourceURL": "https://web.dev/js/index-ffde4443.js",
      "sourceFunctionName": "myClickHandler",
      "sourceCharPosition": 17796,
      "startTime": 11803.199999999255,
      "window": [Window object],
      "windowAttribution": "self"
    }
  ],
  "startTime": 11802.400000000373,
  "styleAndLayoutStart": 11858.800000000745
}

To get a JSON string, you can use JSON.stringify(entry) directly; it will call toJSON() automatically.

Specifications

Specification
Long Animation Frames API
# dom-performancelonganimationframetiming-tojson

Browser compatibility

BCD tables only load in the browser

See also