PerformanceEntry.toJSON()

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

Syntax

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.

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:

{
  "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

BCD tables only load in the browser

See also