The toJSON()
method of the PerformanceLongTaskTiming
interface is a serializer; it returns a JSON representation of the PerformanceLongTaskTiming
object.
A JSON
object that is the serialization of the PerformanceLongTaskTiming
object.
In this example, calling entry.toJSON()
returns a JSON representation of the PerformanceLongTaskTiming
object.
const observer = new PerformanceObserver((list) => {
list.getEntries().forEach((entry) => {
console.log(entry.toJSON());
});
});
observer.observe({ type: "longtask", buffered: true });
This would log a JSON object like so:
{
"name": "self",
"entryType": "longtask",
"startTime": 183,
"duration": 60,
"attribution": [
{
"name": "unknown",
"entryType": "taskattribution",
"startTime": 0,
"duration": 0,
"containerType": "window",
"containerSrc": "",
"containerId": "",
"containerName": ""
}
]
}
To get a JSON string, you can use JSON.stringify(entry)
directly; it will call toJSON()
automatically.