PerformanceScriptTiming: 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 PerformanceScriptTiming interface is a serializer; it returns a JSON representation of the PerformanceScriptTiming object.

Syntax

js
toJSON()

Parameters

None.

Return value

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

Examples

Using the toJSON method

In this example, calling entry.toJSON() returns a JSON representation of the first PerformanceScriptTiming object available in an observed long animation frame.

js
const observer = new PerformanceObserver((list) => {
  list.getEntries().forEach((entry) => {
    console.log(entry.scripts[0].toJSON());
  });
});

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

This would log a JSON object like so:

json
{
  "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"
}

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

Specifications

Specification
Long Animation Frames API
# dom-performancescripttiming-tojson

Browser compatibility

BCD tables only load in the browser

See also