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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

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.

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