locales Optional

A string with a BCP 47 language tag or an Intl.Locale instance, or an array of such locale identifiers. For the general form and interpretation of the locales argument, see the parameter description on the Intl main page.

options Optional

An object containing the following properties, in the order they are retrieved (all of them are optional):

localeMatcher

The locale matching algorithm to use. Possible values are "lookup" and "best fit"; the default is "best fit". For information about this option, see Locale identification and negotiation.

granularity

How granularly should the input be split. Possible values are:

"grapheme" (default)

Split the input into segments at grapheme cluster (user-perceived character) boundaries, as determined by the locale.

"word"

Split the input into segments at word boundaries, as determined by the locale.

"sentence"

Split the input into segments at sentence boundaries, as determined by the locale.

A new Intl.Segmenter instance.

RangeError

Thrown if locales or options contain invalid values.

The following example shows how to count words in a string using the Japanese language (where splitting the string using String methods would have given an incorrect result).

const text = "吾輩は猫である。名前はたぬき。";
const japaneseSegmenter = new Intl.Segmenter("ja-JP", { granularity: "word" });
console.log(
  [...japaneseSegmenter.segment(text)].filter((segment) => segment.isWordLike)
    .length,
);
// 8, as the text is segmented as '吾輩'|'は'|'猫'|'で'|'ある'|'。'|'名前'|'は'|'たぬき'|'。'