Temporal.Duration.prototype.toJSON()

Limited availability

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

The toJSON() method of Temporal.Duration instances returns a string representing this duration in the same ISO 8601 format as calling toString(). It is intended to be implicitly called by JSON.stringify().

Syntax

js
toJSON()

Parameters

None.

Return value

A string representing the given duration in the ISO 8601 format, with as much subsecond precision as necessary to represent the duration accurately.

Description

The toJSON() method is automatically called by JSON.stringify() when a Temporal.Duration object is stringified. This method is generally intended to, by default, usefully serialize Temporal.Duration objects during JSON serialization, which can then be deserialized using the Temporal.Duration.from() function as the reviver of JSON.parse().

Examples

Using toJSON()

js
const duration = Temporal.Duration.from({ hours: 1, minutes: 30, seconds: 15 });
const durationStr = duration.toJSON(); // 'PT1H30M15S'
const d2 = Temporal.Duration.from(durationStr);

JSON serialization and parsing

This example shows how Temporal.Duration can be serialized as JSON without extra effort, and how to parse it back.

js
const duration = Temporal.Duration.from({ hours: 1, minutes: 30, seconds: 15 });
const jsonStr = JSON.stringify({ data: duration }); // '{"data":"PT1H30M15S"}'
const obj = JSON.parse(jsonStr, (key, value) => {
  if (key === "data") {
    return Temporal.Duration.from(value);
  }
  return value;
});

Specifications

Specification
Temporal
# sec-temporal.duration.prototype.tojson

Browser compatibility

desktop mobile server
Chrome
Edge
Firefox
Opera
Safari
Chrome Android
Firefox for Android
Opera Android
Safari on iOS
Samsung Internet
WebView Android
WebView on iOS
Bun
Deno
Node.js
toJSON
Chrome – Full support
Chrome 144 (Release date: 2026-01-13)
footnote Full support
Edge – Full support
Edge 144 (Release date: 2026-01-21)
footnote Full support
Firefox – Full support
Firefox 139 (Release date: 2025-05-27)
footnote Full support
Opera – Full support
Opera 128 (Release date: 2026-02-26)
footnote Full support
Safari – Preview support
Safari TP
footnote
footnote See bug 223166
footnote Preview browser support
Chrome Android – Full support
Chrome Android 144 (Release date: 2026-01-13)
footnote Full support
Firefox for Android – Full support
Firefox for Android 139 (Release date: 2025-05-27)
footnote Full support
Opera Android – Full support
Opera Android 95 (Release date: 2026-02-11)
footnote Full support
Safari on iOS – No support
Safari on iOS
footnote No support
Samsung Internet – No support
Samsung Internet
footnote No support
WebView Android – Full support
WebView Android 144 (Release date: 2026-01-13)
footnote Full support
WebView on iOS – No support
WebView on iOS
footnote No support
Bun – No support
Bun
footnote No support
Deno – Full support
Deno 2.7 (Release date: 2026-02-25)
footnote Full support
Node.js – No support
Node.js
footnote No support

Legend

Tip: you can click/tap on a cell for more information.

Full support
Full support
In development. Supported in a pre-release version.
In development. Supported in a pre-release version.
No support
No support
See implementation notes.

See also