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

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 an object like so:

js
({
  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,
  windowAttribution: "self",
});

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