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PerformanceLongTaskTiming: toJSON() method

Experimental: This is an experimental technology
Check the Browser compatibility table carefully before using this in production.

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

Syntax

js

toJSON()

Parameters

None.

Return value

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

Examples

Using the toJSON method

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

js

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

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

This would log a JSON object like so:

json

{
  "name": "self",
  "entryType": "longtask",
  "startTime": 183,
  "duration": 60,
  "attribution": [
    {
      "name": "unknown",
      "entryType": "taskattribution",
      "startTime": 0,
      "duration": 0,
      "containerType": "window",
      "containerSrc": "",
      "containerId": "",
      "containerName": ""
    }
  ]
}

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

Specifications

Specification
Long Tasks API
# dom-performancelongtasktiming-tojson

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 58 79 No No 45 No 58 58 No 43 No 7.0

See also

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Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://developer.mozilla.org/en-US/docs/Web/API/PerformanceLongTaskTiming/toJSON