NotRestoredReasons: toJSON() method
Limited availability
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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 NotRestoredReasons interface returns a JSON-serializable plain object representing the NotRestoredReasons object.
The method is automatically called by JSON.stringify() when a NotRestoredReasons 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. When the returned object is passed to JSON.stringify(), the objects in the reasons and children arrays are further serialized using NotRestoredReasonDetails.toJSON() and NotRestoredReasons.toJSON(), respectively, when the arrays are not null.
Examples
Calling toJSON() directly
This example obtains a NotRestoredReasons object from the first navigation entry. Calling toJSON() directly returns a plain object. Its properties have the same values as the corresponding properties of the original object.
const navEntries = performance.getEntriesByType("navigation");
const navEntry = navEntries[0];
const reasons = navEntry.notRestoredReasons;
const json = reasons.toJSON();
console.log(json); // A plain object
console.log(typeof json); // "object"
console.log(json.url); // Same value as reasons.url
Serializing to a JSON string
The object from the previous example is serialized using JSON.stringify(), which calls the toJSON() method automatically.
console.log(JSON.stringify(reasons));
This would log a JSON string like so (formatted for readability):
{
"src": null,
"id": null,
"url": "https://example.com/",
"name": null,
"reasons": [
{
"reason": "masked"
}
],
"children": [
{
"src": "https://other.example/frame.html",
"id": "frame",
"url": null,
"name": null,
"reasons": null,
"children": null
}
]
}
Specifications
| Specification |
|---|
| HTML # notrestoredreasons |