TaskAttributionTiming: toJSON() method

Limited availability

This feature is not Baseline because it does not work in some of the most widely-used browsers.

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Experimental: This is an experimental technology
Check the Browser compatibility table carefully before using this in production.

The toJSON() method of the TaskAttributionTiming interface returns a JSON-serializable plain object representing the TaskAttributionTiming object.

The method is automatically called by JSON.stringify() when a TaskAttributionTiming object is encountered during JSON serialization.

Syntax

js
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 TaskAttributionTiming object. Calling toJSON() directly returns a plain object. Its properties have the same values as the corresponding properties of the original object.

js
const observer = new PerformanceObserver((list) => {
  list.getEntries().forEach((entry) => {
    entry.attribution.forEach((attribution) => {
      const json = attribution.toJSON();
      console.log(json); // A plain object
      console.log(typeof json); // "object"
      console.log(json.containerType); // Same value as attribution.containerType
    });
  });
});

observer.observe({ type: "longtask", 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.

js
console.log(JSON.stringify(attribution));

This would log a JSON string like so (formatted for readability):

json
{
  "name": "unknown",
  "entryType": "taskattribution",
  "startTime": 0,
  "duration": 0,
  "navigationId": 2463,
  "containerType": "window",
  "containerSrc": "",
  "containerId": "",
  "containerName": ""
}

Specifications

This feature does not appear to be defined in any specification.

Browser compatibility

See also