formatRelativeDateTime

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Signature

formatRelativeDateTime(value: string, locale?: string, options?: FormatRelativeDateTimeOptions): string

import { formatRelativeDateTime } from "@northguild/gmt/plain/format";

Format the relative time between a plain date-time and a reference date-time.

• Auto-picks the display unit (second through year) based on the distance, unless largestUnit forces one.
• roundingMethod controls how the distance rounds to the display unit.

Parameters

Parameter	Type	Description
value	string	ISO date-time string to format
locale	string	optional: BCP 47 locale tag

Options

options

Option	Type	Default
style?	"long" | "short" | "narrow"	—
numeric?	"always" | "auto"	—
largestUnit?	RelativeUnit	—
roundingMethod?	RelativeRoundingMethod	—
reference?	string	—

Returns

the formatted relative-time string, or “” on invalid input

Related types

• FormatRelativeDateTimeOptions

Examples

formatRelativeDateTime("2026-03-17T09:00:00", "en-GB", { style: "long" }) // "in 3 hours"
formatRelativeDateTime(value, "en-US", { roundingMethod: "floor" }) // rounds toward the earlier boundary
formatRelativeDateTime("not-a-date") // ""

Source

plain/format/formatRelativeDateTime.ts