IntlCollator

Intl.Collator is a constructor in the ECMAScript Internationalization API that creates objects capable of comparing strings according to locale- and language-specific rules. It encapsulates locale data and options so that sorting and searching can be performed in a way that respects linguistic conventions for the selected language or region. Implementations rely on Unicode CLDR data and are available in modern web browsers and Node.js.

An Intl.Collator object provides a compare(a, b) function. The function returns a negative number if a comes before b, zero if they are considered equivalent, or a positive number if a comes after b, according to the configured locale and options. The same compare function can be used as a comparator when sorting arrays. The constructor also exposes supportedLocalesOf(locales) to query which locales are available, and resolvedOptions() to inspect the actual locale and option values being used.

Locales and options. You create a collator with new Intl.Collator(locales, options). Locales can be a string or an array of strings. Options include localeMatcher ('lookup' or 'best fit'), usage ('sort' or 'search'), numeric (true to compare numbers numerically), caseFirst ('upper', 'lower', or 'false'), sensitivity ('base', 'accent', 'case', or 'variant'), ignorePunctuation (true or false), and collator-specific rules such as collation. Not all options are supported by every environment.

Example usage. const coll = new Intl.Collator('fr-FR', { numeric: true, sensitivity: 'base' }); const arr = ['2','10','1']; arr.sort(coll.compare) sorts numerically according to French conventions. Locale data and option support may vary by engine, so resolvedOptions() can help confirm exact behavior.

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