PerformanceEntry: 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 is a serializer; it returns a JSON representation of the PerformanceEntry object.
Syntax
js
toJSON()
Parameters
None.
Return value
A JSON object that is the serialization of the PerformanceEntry object.
Examples
Using the toJSON method
In this example, calling entry.toJSON() returns a JSON representation of the PerformanceMark object.
js
performance.mark("debug-marker", {
detail: "debugging-marker-123",
});
const observer = new PerformanceObserver((list) => {
list.getEntries().forEach((entry) => {
console.log(entry.toJSON());
});
});
observer.observe({ entryTypes: ["mark"] });
This would log a JSON object like so:
json
{
"name": "debug-marker",
"entryType": "mark",
"startTime": 158361,
"duration": 0
}
Note that it doesn't contain PerformanceMark's detail property.
To get a JSON string, you can use JSON.stringify(entry) directly; it will call toJSON() automatically.
Specifications
| Specification |
|---|
| Performance Timeline # dom-performanceentry-tojson |
Browser compatibility
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Legend
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- Full support
- Full support