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

None.

A JSON object that is the serialization of the PerformanceEventTiming object.

The JSON doesn't contain the target property because it is of type Node, which doesn't provide a toJSON() operation.

In this example, calling entry.toJSON() returns a JSON representation of the PerformanceEventTiming object.

const observer = new PerformanceObserver((list) => {
  list.getEntries().forEach((entry) => {
    console.log(entry.toJSON());
  });
});

observer.observe({ type: "event", buffered: true });

This would log a JSON object like so:

{
  "name": "dragover",
  "entryType": "event",
  "startTime": 67090751.599999905,
  "duration": 128,
  "processingStart": 67090751.70000005,
  "processingEnd": 67090751.900000095,
  "cancelable": true
}

To get a JSON string, you can use JSON.stringify(entry) directly; it will call toJSON() automatically.

• JSON