PerformancePaintTiming: toJSON() method

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since April 2021.

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

Syntax

js
toJSON()

Parameters

None.

Return value

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

Examples

Using the toJSON method

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

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

observer.observe({ type: "paint", buffered: true });

This would log a JSON object like so:

json
{
  "name": "first-contentful-paint",
  "entryType": "paint",
  "startTime": 234.5,
  "duration": 0
}

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

Specifications

Specification
Paint Timing
# dom-performancepainttiming-tojson

Browser compatibility

desktop mobile
Chrome
Edge
Firefox
Opera
Safari
Chrome Android
Firefox for Android
Opera Android
Safari on iOS
Samsung Internet
WebView Android
WebView on iOS
toJSON
Chrome – Full support
Chrome 60 (Release date: 2017-07-25)
footnote Full support
Edge – Full support
Edge 79 (Release date: 2020-01-15)
footnote Full support
Firefox – Full support
Firefox 84 (Release date: 2020-12-15)
footnote Full support
Opera – Full support
Opera 47 (Release date: 2017-08-09)
footnote Full support
Safari – Full support
Safari 14.1 (Release date: 2021-04-26)
footnote Full support
Chrome Android – Full support
Chrome Android 60 (Release date: 2017-08-01)
footnote Full support
Firefox for Android – Full support
Firefox for Android 84 (Release date: 2020-12-15)
footnote Full support
Opera Android – Full support
Opera Android 44 (Release date: 2017-12-11)
footnote Full support
Safari on iOS – Full support
Safari on iOS 14.5 (Release date: 2021-04-26)
footnote Full support
Samsung Internet – Full support
Samsung Internet 8 (Release date: 2018-07-18)
footnote Full support
WebView Android – Full support
WebView Android 60 (Release date: 2017-08-01)
footnote Full support
WebView on iOS – Full support
WebView on iOS 14.5 (Release date: 2021-04-26)
footnote Full support

Legend

Tip: you can click/tap on a cell for more information.

Full support
Full support

See also