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Intl.RelativeTimeFormat.prototype.format()

The format() method of Intl.RelativeTimeFormat instances formats a value and unit according to the locale and formatting options of this Intl.RelativeTimeFormat object.

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Syntax

js
format(value, unit)

Parameters

value

Numeric value to use in the internationalized relative time message.

unit

Unit to use in the relative time internationalized message. Possible values are: "year", "quarter", "month", "week", "day", "hour", "minute", "second". Plural forms are also permitted.

Return value

A string representing the given value and unit formatted according to the locale and formatting options of this Intl.RelativeTimeFormat object.

Examples

Basic format usage

The following example shows how to create a relative time formatter using the English language.

js
// Create a relative time formatter in your locale
// with default values explicitly passed in.
const rtf = new Intl.RelativeTimeFormat("en", {
  localeMatcher: "best fit", // other values: "lookup"
  numeric: "always", // other values: "auto"
  style: "long", // other values: "short" or "narrow"
});

// Format relative time using negative value (-1).
rtf.format(-1, "day"); // "1 day ago"

// Format relative time using positive value (1).
rtf.format(1, "day"); // "in 1 day"

Using the auto option

If numeric:auto option is passed, it will produce the string yesterday, today, or tomorrow instead of 1 day ago, in 0 days, or in 1 day. This allows to not always have to use numeric values in the output.

js
// Create a relative time formatter in your locale
// with numeric: "auto" option value passed in.
const rtf = new Intl.RelativeTimeFormat("en", { numeric: "auto" });

// Format relative time using negative value (-1).
rtf.format(-1, "day"); // "yesterday"

rtf.format(0, "day"); // "today"

// Format relative time using positive day unit (1).
rtf.format(1, "day"); // "tomorrow"

Specifications

Browser compatibility

Desktop Mobile Server
Chrome Edge Firefox Opera Safari Chrome Android Firefox for Android Opera Android Safari on IOS Samsung Internet WebView Android Deno Node.js
format 71 79 65 58 14 71 65 50 14 10.0 71 1.8
12.0.0Before version 13.0.0, only the locale data for en-US is available by default. See the RelativeTimeFormat() constructor for more details.

See also

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Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Intl/RelativeTimeFormat/format