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 October 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
Enable JavaScript to view this browser compatibility table.