toRFC3339

Converts a date to RFC 3339 format Format: YYYY-MM-DDTHH:mm:ssZ or YYYY-MM-DDTHH:mm:ss+HH:mm RFC 3339 is a profile of ISO 8601, but without milliseconds by default

Available since v2.0.0

Import

import { toRFC3339 } from '@helpers4/date';

Signature

toRFC3339(date: DateLike, includeMilliseconds: boolean): string | null

Parameters

Parameter	Type	Description
date	DateLike	Date to convert (Date object, timestamp, or date string)
includeMilliseconds	boolean	Whether to include milliseconds (default: false)

Returns

string | null — RFC 3339 formatted string or null if invalid date

Examples

toRFC3339

toRFC3339(new Date('2025-01-19T12:30:45.123Z')) // '2025-01-19T12:30:45Z'
toRFC3339(new Date('2025-01-19T12:30:45.123Z'), true) // '2025-01-19T12:30:45.123Z'

Related Types

DateLike

A value that can be converted to a Date.

• Date — used as-is (validated for Invalid Date)
• number — treated as a timestamp (seconds or milliseconds, auto-detected); 0 is treated as invalid and produces null in ensureDate
• string — parsed via new Date(string)
• EpochMilliseconds — any object with a epochMilliseconds property (e.g. Temporal.Instant, Temporal.ZonedDateTime)

// TODO: When the Temporal API reaches Stage 4 and is available without // flags in all major runtimes, consider narrowing the union to the // concrete Temporal types for stricter type-checking.

type DateLike = Date | number | string | EpochMilliseconds

EpochMilliseconds

An object that exposes an epoch timestamp in milliseconds.

This structural type is satisfied by Temporal.Instant and Temporal.ZonedDateTime (and any future object that carries the same property), so callers can pass Temporal values without importing them.

interface EpochMilliseconds {
  epochMilliseconds: number;
}

Source

View source on GitHub