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PerformanceResourceTiming: toJSON() method

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

Browser compatibility

Desktop Mobile
Chrome Edge Firefox Internet Explorer Opera Safari WebView Android Chrome Android Firefox for Android Opera Android Safari on IOS Samsung Internet
toJSON 45 16 34 No 32 11 45 45 34 32 11 5.0

See also

© 2005–2023 MDN contributors.
Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://developer.mozilla.org/en-US/docs/Web/API/PerformanceResourceTiming/toJSON