Add Intl.locale types

src/lib/es2020.intl.d.ts

@@ -273,4 +273,72 @@ declare namespace Intl {
         unit?: string;
         unitDisplay?: string;
     }
+
+    type LocaleHourCycleKey = "h12" | "h23" | "h11" | "h24";
+    type LocaleCollationCaseFirst = "upper" | "lower" | "false";
+
+    interface LocaleOptions {
+        baseName?: string;
+        calendar?: string;
+        caseFirst?: LocaleCollationCaseFirst;
+        collation?: string;
+        hourCycle?: LocaleHourCycleKey;
+        language?: string;
+        numberingSystem?: string;
+        numeric?: boolean;
+        region?: string;
+        script?: string;
+    }
+
+    interface Locale extends LocaleOptions {
+        /** Gets the most likely values for the language, script, and region of the locale based on existing values. */
+        maximize(): Locale;
+        /** Attempts to remove information about the locale that would be added by calling `Locale.maximize()`. */
+        minimize(): Locale;
+        /** Returns the locale's full locale identifier string. */
+        toString(): BCP47LanguageTag;
+    }
+
+    /**
+     * Constructor creates [Intl.Locale](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Intl/Locale)
+     * objects
+     *
+     * @param tag - A string with a [BCP 47 language tag](http://tools.ietf.org/html/rfc5646).
+     *  For the general form and interpretation of the locales argument,
+     *  see the [`Intl` page](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Intl#Locale_identification_and_negotiation).
+     *
+     * @param options - An [object](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Intl/Locale/Locale#Parameters)
+     *  with some or all of options of the locale.
+     *  An object with some or all of the following properties:
+     *  - `baseName` - A string containing the language, and the script and region if available.
+     *    Possible values are valid BCP47 language tags
+     *  - `calendar` - The part of the Locale that indicates the locale's calendar era.
+     *    Possible values are valid BCP47 calendar keys
+     *  - `caseFirst` - Flag that defines whether case is taken into account for the locale's collation rules.
+     *    Possible values are valid BCP47 collation case levels
+     *  - `collation` - The collation type used for sorting
+     *    Possible values are valid BCP47 collation keys
+     *  - `hourCycle` - The time keeping format convention used by the locale.
+     *    Possible values are valid BCP47 hour cycle keys
+     *  - `language` - The primary language subtag associated with the locale.
+     *    Possible values are valid BCP47 primary language subtags
+     *  - `numberingSystem` - The numeral system used by the locale.
+     *    Possible values are valid BCP47 numbering system keys
+     *  - `numeric` - Flag that defines whether the locale has special collation handling for numeric characters.
+     *    Possible values are booleans
+     *  - `region` - The region of the world (usually a country) associated with the locale.
+     *    Possible values are region codes as defined by ISO 3166-1
+     *  - `script` - The script used for writing the particular language used in the locale.
+     *    Possible values are script codes as defined by ISO 15924
+     *
+     * @returns [Intl.Locale](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Intl/Locale) object.
+     *
+     * [MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Intl/Locale).
+     *
+     * [Specification](https://tc39.es/ecma402/#sec-intl-locale-constructor).
+     */
+    const Locale: {
+        new (tag?: BCP47LanguageTag, options?: LocaleOptions): Locale;
+    };
+
 }