[js] Add externs for the `Intl.DisplayNames` class (#10357)

Fixes #10330

std/js/lib/intl/DisplayNames.hx

@@ -0,0 +1,133 @@
+/*
+ * Copyright (C)2005-2021 Haxe Foundation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ */
+
+package js.lib.intl;
+
+/**
+	The `Intl.DisplayNames` object enables the consistent translation of language,
+	region and script display names.
+**/
+@:native("Intl.DisplayNames")
+extern class DisplayNames {
+
+	/**
+		Creates a new `Intl.DisplayNames` object.
+	**/
+	@:overload(function(?locales: Array<String>, ?options: DisplayNamesOptions): Void {})
+	function new(?locales: String, ?options: DisplayNamesOptions);
+
+	/**
+		Receives a code and returns a string based on the locale and options
+		provided when instantiating `Intl.DisplayNames`.
+	**/
+	function of(code: String): String;
+
+	/**
+		Returns a new object with properties reflecting the locale and formatting options
+		computed during initialization of the object.
+	**/
+	function resolvedOptions(): DisplayNamesResolvedOptions;
+
+	/**
+		Returns an array containing those of the provided locales that are supported
+		in display names without having to fall back to the runtime's default locale.
+	**/
+	@:overload(function(locales: Array<String>, ?options: DisplayNamesSupportedLocalesOfOptions): Array<String> {})
+	static function supportedLocalesOf(locales: String, ?options: DisplayNamesSupportedLocalesOfOptions): Array<String>;
+}
+
+enum abstract DisplayNamesFallback(String) {
+	var Code = "code";
+	var None = "none";
+}
+
+typedef DisplayNamesOptions = {
+	/**
+		The fallback to use.
+		The default is `Code`.
+	**/
+	var fallback: DisplayNamesFallback;
+
+	/**
+		The locale matching algorithm to use.
+		The default is `BestFit`.
+	**/
+	var ?localeMatcher: LocaleMatcher;
+
+	/**
+		The formatting style to use.
+		The default is `Long`.
+	**/
+	var ?style: DisplayNamesStyle;
+
+	/**
+		The type to use.
+		The default is `Language`.
+	**/
+	var ?type: DisplayNamesType;
+}
+
+typedef DisplayNamesResolvedOptions = {
+	/**
+		The value provided for this property in the `options` argument of the constructor
+		or the default value (`Code`).
+	**/
+	final fallback: DisplayNamesFallback;
+
+	/**
+		The BCP 47 language tag for the locale actually used.
+	**/
+	final locale: String;
+
+	/**
+		The value provided for this property in the `options` argument of the constructor
+		or the default value (`Long`).
+	**/
+	final style: DisplayNamesStyle;
+
+	/**
+		The value provided for this property in the `options` argument of the constructor
+		or the default value (`Language`).
+	**/
+	final type: DisplayNamesType;
+}
+
+enum abstract DisplayNamesStyle(String) {
+	var Long = "long";
+	var Narrow = "narrow";
+	var Short = "short";
+}
+
+typedef DisplayNamesSupportedLocalesOfOptions = {
+	/**
+		The locale matching algorithm to use.
+		The default is `BestFit`.
+	 */
+	var ?localeMatcher: LocaleMatcher;
+}
+
+enum abstract DisplayNamesType(String) {
+	var Currency = "currency";
+	var Language = "language";
+	var Region = "region";
+	var Script = "script";
+}