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Intl.RelativeTimeFormat

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The Intl.RelativeTimeFormat object enables language-sensitive relative time formatting.

{{InteractiveExample("JavaScript Demo: Intl.RelativeTimeFormat")}}

```js interactive-example const rtf1 = new Intl.RelativeTimeFormat("en", { style: "short" });

console.log(rtf1.format(3, "quarter")); // Expected output: "in 3 qtrs."

console.log(rtf1.format(-1, "day")); // Expected output: "1 day ago"

const rtf2 = new Intl.RelativeTimeFormat("es", { numeric: "auto" });

console.log(rtf2.format(2, "day")); // Expected output: "pasado mañana"

## Constructor

- {{jsxref("Intl/RelativeTimeFormat/RelativeTimeFormat", "Intl.RelativeTimeFormat()")}}
  - : Creates a new `Intl.RelativeTimeFormat` object.

## Static methods

- {{jsxref("Intl/RelativeTimeFormat/supportedLocalesOf", "Intl.RelativeTimeFormat.supportedLocalesOf()")}}
  - : Returns an array containing those of the provided locales that are supported without having to fall back to the runtime's default locale.

## Instance properties

These properties are defined on `Intl.RelativeTimeFormat.prototype` and shared by all `Intl.RelativeTimeFormat` instances.

- {{jsxref("Object/constructor", "Intl.RelativeTimeFormat.prototype.constructor")}}
  - : The constructor function that created the instance object. For `Intl.RelativeTimeFormat` instances, the initial value is the {{jsxref("Intl/RelativeTimeFormat/RelativeTimeFormat", "Intl.RelativeTimeFormat")}} constructor.
- `Intl.RelativeTimeFormat.prototype[Symbol.toStringTag]`
  - : The initial value of the [`[Symbol.toStringTag]`](/en-US/docs/Web/JavaScript/Reference/Global_Objects/Symbol/toStringTag) property is the string `"Intl.RelativeTimeFormat"`. This property is used in {{jsxref("Object.prototype.toString()")}}.

## Instance methods

- {{jsxref("Intl/RelativeTimeFormat/format", "Intl.RelativeTimeFormat.prototype.format()")}}
  - : Formats a `value` and a `unit` according to the locale and formatting options of the given `Intl.RelativeTimeFormat` object.
- {{jsxref("Intl/RelativeTimeFormat/formatToParts", "Intl.RelativeTimeFormat.prototype.formatToParts()")}}
  - : Returns an {{jsxref("Array")}} of objects representing the relative time format in parts that can be used for custom locale-aware formatting.
- {{jsxref("Intl/RelativeTimeFormat/resolvedOptions", "Intl.RelativeTimeFormat.prototype.resolvedOptions()")}}
  - : Returns a new object with properties reflecting the locale and formatting options computed during initialization of the object.

## Examples

### Basic format usage

The following example shows how to use a relative time formatter for 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 formatToParts#

The following example shows how to create a relative time formatter returning formatted parts.

const rtf = new Intl.RelativeTimeFormat("en", { numeric: "auto" });

// Format relative time using the day unit.
rtf.formatToParts(-1, "day");
// [{ type: "literal", value: "yesterday"}]

rtf.formatToParts(100, "day");
// [
//   { type: "literal", value: "in " },
//   { type: "integer", value: "100", unit: "day" },
//   { type: "literal", value: " days" }
// ]

Specifications#

{{Specifications}}

Browser compatibility#

{{Compat}}

See also#