Performance: 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.
Note: This feature is available in Web Workers.
The toJSON() method of the Performance interface is a serializer; it returns a JSON representation of the Performance object.
Syntax
toJSON()
Parameters
None.
Return value
A JSON object that is the serialization of the Performance object.
The returned JSON doesn't contain the eventCounts property because it is of type EventCounts, which doesn't provide a toJSON() operation.
Note:
The JSON object contains the serialization of the deprecated performance.timing and performance.navigation properties. To get a JSON representation of the newer PerformanceNavigationTiming interface, call PerformanceNavigationTiming.toJSON() instead.
Examples
Using the toJSON method
In this example, calling performance.toJSON() returns a JSON representation of the Performance object.
performance.toJSON();
This would log a JSON object like so:
{
"timeOrigin": 1668077531367.4,
"timing": {
"connectStart": 1668077531372,
"navigationStart": 1668077531367,
"secureConnectionStart": 0,
"fetchStart": 1668077531372,
"domContentLoadedEventStart": 1668077531580,
"responseStart": 1668077531372,
"domInteractive": 1668077531524,
"domainLookupEnd": 1668077531372,
"responseEnd": 1668077531500,
"redirectStart": 0,
"requestStart": 1668077531372,
"unloadEventEnd": 0,
"unloadEventStart": 0,
"domLoading": 1668077531512,
"domComplete": 1668077531585,
"domainLookupStart": 1668077531372,
"loadEventStart": 1668077531585,
"domContentLoadedEventEnd": 1668077531580,
"loadEventEnd": 1668077531585,
"redirectEnd": 0,
"connectEnd": 1668077531372
},
"navigation": {
"type": 0,
"redirectCount": 0
}
}
To get a JSON string, you can use JSON.stringify(performance) directly; it will call toJSON() automatically.
Specifications
| Specification |
|---|
| High Resolution Time # dom-performance-tojson |
Browser compatibility
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