Intl.RelativeTimeFormat

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

Constructor

Intl.RelativeTimeFormat()
- : Creates a new Intl.RelativeTimeFormat object.

Static methods

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.

Intl.RelativeTimeFormat.prototype.constructor
- : The constructor function that created the instance object. For Intl.RelativeTimeFormat instances, the initial value is the Intl.RelativeTimeFormat constructor.
Intl.RelativeTimeFormat.prototype[@@toStringTag]
- : The initial value of the @@toStringTag property is the string "Intl.RelativeTimeFormat". This property is used in Object.prototype.toString.

Instance methods

Intl.RelativeTimeFormat.prototype.format()
- : Formats a value and a unit according to the locale and formatting options of the given Intl.RelativeTimeFormat object.
Intl.RelativeTimeFormat.prototype.formatToParts()
- : Returns an Array of objects representing the relative time format in parts that can be used for custom locale-aware formatting.
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.

// 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" }
// ]