PerformanceTimingConfidence: toJSON() method
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The toJSON() method of the PerformanceTimingConfidence interface returns a JSON-serializable plain object representing the PerformanceTimingConfidence object.
The method is automatically called by JSON.stringify() when a PerformanceTimingConfidence object is encountered during JSON serialization.
Syntax
toJSON()
Parameters
None.
Return value
A JSON-serializable plain object containing the following properties:
Each property's value is copied as-is.
Examples
Calling toJSON() directly
This example obtains a PerformanceTimingConfidence object. Calling toJSON() directly returns a plain object. Its properties have the same values as the corresponding properties of the original object.
const observer = new PerformanceObserver((list) => {
list.getEntries().forEach((entry) => {
const confidence = entry.confidence;
const json = confidence.toJSON();
console.log(json); // A plain object
console.log(typeof json); // "object"
console.log(json.value); // Same value as confidence.value
});
});
observer.observe({ type: "navigation", buffered: true });
Serializing to a JSON string
Within the callback from the previous example, the same object can be serialized using JSON.stringify(), which calls the toJSON() method automatically.
console.log(JSON.stringify(confidence));
This would log a JSON string like so (formatted for readability):
{
"randomizedTriggerRate": 0.4994798,
"value": "high"
}
Specifications
| Specification |
|---|
| Navigation Timing Level 2 # dom-performancetimingconfidence-tojson |