PerformanceResourceTiming: 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 September 2017.

Note: This feature is available in Web Workers.

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

Syntax

js
toJSON()

Parameters

None.

Return value

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

Examples

Using the toJSON method

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

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

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

This would log a JSON object like so:

json
{
  "name": "https://upload.wikimedia.org/wikipedia/en/thumb/4/4a/Commons-logo.svg/31px-Commons-logo.svg.png",
  "entryType": "resource",
  "startTime": 110.80000001192093,
  "duration": 11.599999994039536,
  "initiatorType": "img",
  "nextHopProtocol": "h2",
  "renderBlockingStatus": "non-blocking",
  "workerStart": 0,
  "redirectStart": 0,
  "redirectEnd": 0,
  "fetchStart": 110.80000001192093,
  "domainLookupStart": 110.80000001192093,
  "domainLookupEnd": 110.80000001192093,
  "connectStart": 110.80000001192093,
  "connectEnd": 110.80000001192093,
  "secureConnectionStart": 110.80000001192093,
  "requestStart": 117.30000001192093,
  "responseStart": 120.40000000596046,
  "responseStatus": 200,
  "responseEnd": 122.40000000596046,
  "transferSize": 0,
  "encodedBodySize": 880,
  "decodedBodySize": 880,
  "serverTiming": [
    {
      "name": "cache",
      "duration": 0,
      "description": "hit-front"
    },
    {
      "name": "host",
      "duration": 0,
      "description": "cp3061"
    }
  ]
}

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

Specifications

Specification
Resource Timing
# dom-performanceresourcetiming-tojson

Browser compatibility

Report problems with this compatibility data on GitHub
desktopmobileserver
Chrome
Edge
Firefox
Opera
Safari
Chrome Android
Firefox for Android
Opera Android
Safari on iOS
Samsung Internet
WebView Android
WebView on iOS
Deno
Node.js
toJSON

Legend

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

Full support
Full support
Has more compatibility info.

See also