Intl: add supportedLocalesOf()

Author: duonglaiquang

src/main/java/org/htmlunit/javascript/host/intl/DateTimeFormat.java

@@ -37,6 +37,7 @@
 import org.htmlunit.javascript.configuration.JsxClass;
 import org.htmlunit.javascript.configuration.JsxConstructor;
 import org.htmlunit.javascript.configuration.JsxFunction;
+import org.htmlunit.javascript.configuration.JsxStaticFunction;
 import org.htmlunit.javascript.host.Window;
 import org.htmlunit.util.StringUtils;
 
@@ -305,6 +306,18 @@ public Scriptable resolvedOptions() {
         return options;
     }
 
+    /**
+     * Returns an array containing those of the provided locales that are supported
+     * without having to fall back to the default locale.
+     * @param localesArgument A string with a BCP 47 language tag, or an array of such strings
+     * @param options unused
+     * @return an array containing supported locales
+     */
+    @JsxStaticFunction
+    public static Scriptable supportedLocalesOf(final Scriptable localesArgument, final Scriptable options) {
+        return Intl.supportedLocalesOf(localesArgument);
+    }
+
     /**
      * Helper.
      */

src/main/java/org/htmlunit/javascript/host/intl/Intl.java

@@ -24,6 +24,7 @@
 import java.util.Map;
 import java.util.Set;
 
+import org.apache.commons.lang3.LocaleUtils;
 import org.htmlunit.BrowserVersion;
 import org.htmlunit.corejs.javascript.Context;
 import org.htmlunit.corejs.javascript.Function;
@@ -60,7 +61,7 @@ public static void init(final Scriptable scope, final ScriptableObject globalThi
         intl.setParentScope(scope);
         intl.defineProperties(scope, browserVersion);
 
-        // Configure static functions
+        // Configure static functions (getCanonicalLocales)
         final ClassConfiguration intlConfig = AbstractJavaScriptConfiguration.getClassConfiguration(Intl.class, browserVersion);
         if (intlConfig != null) {
             defineStaticFunctions(intlConfig, intl, intl);
@@ -173,4 +174,36 @@ else if (elem instanceof ScriptableObject) {
 
         return cx.newArray(TopLevel.getTopLevelScope(thisObj), canonicalLocales.toArray());
     }
+
+    /**
+     * Shared utility for {@code supportedLocalesOf} implementations.
+     * @param localesArgument the locales argument
+     * @return a Scriptable array of supported locale strings
+     */
+    static Scriptable supportedLocalesOf(final Scriptable localesArgument) {
+        final String[] locales;
+        if (localesArgument instanceof NativeArray array) {
+            locales = new String[(int) array.getLength()];
+            for (int i = 0; i < locales.length; i++) {
+                locales[i] = JavaScriptEngine.toString(array.get(i));
+            }
+        }
+        else {
+            locales = new String[] {JavaScriptEngine.toString(localesArgument)};
+        }
+
+        final List<String> supportedLocales = new ArrayList<>();
+        for (final String locale : locales) {
+            if (locale.isEmpty()) {
+                throw JavaScriptEngine.rangeError("Invalid language tag: " + locale);
+            }
+            final java.util.Locale l = java.util.Locale.forLanguageTag(locale);
+            if (LocaleUtils.isAvailableLocale(l)) {
+                supportedLocales.add(locale);
+            }
+        }
+
+        return Context.getCurrentContext().newArray(
+                TopLevel.getTopLevelScope(localesArgument), supportedLocales.toArray());
+    }
 }

src/main/java/org/htmlunit/javascript/host/intl/NumberFormat.java

@@ -32,6 +32,7 @@
 import org.htmlunit.javascript.configuration.JsxClass;
 import org.htmlunit.javascript.configuration.JsxConstructor;
 import org.htmlunit.javascript.configuration.JsxFunction;
+import org.htmlunit.javascript.configuration.JsxStaticFunction;
 import org.htmlunit.javascript.host.Window;
 import org.htmlunit.util.StringUtils;
 
@@ -209,6 +210,18 @@ public Scriptable resolvedOptions() {
         return JavaScriptEngine.newObject(getParentScope());
     }
 
+    /**
+     * Returns an array containing those of the provided locales that are supported
+     * without having to fall back to the default locale.
+     * @param localesArgument A string with a BCP 47 language tag, or an array of such strings
+     * @param options unused
+     * @return an array containing supported locales
+     */
+    @JsxStaticFunction
+    public static Scriptable supportedLocalesOf(final Scriptable localesArgument, final Scriptable options) {
+        return Intl.supportedLocalesOf(localesArgument);
+    }
+
     /**
      * Helper.
      */

src/test/java/org/htmlunit/javascript/host/intl/DateTimeFormatTest.java

@@ -434,4 +434,27 @@ private void locale(final String language) throws Exception {
             shutDownAll();
         }
     }
+
+    /**
+     * @throws Exception if the test fails
+     */
+    @Test
+    @Alerts({"en", "en,ja", ""})
+    public void supportedLocalesOf() throws Exception {
+        final String html = DOCTYPE_HTML
+                + "<html><head>\n"
+                + "<script>\n"
+                + LOG_TITLE_FUNCTION
+                + "  function test() {\n"
+                + "    log(Intl.DateTimeFormat.supportedLocalesOf('en'));\n"
+                + "    log(Intl.DateTimeFormat.supportedLocalesOf(['en', 'xx-YY', 'ja']));\n"
+                + "    log(Intl.DateTimeFormat.supportedLocalesOf([]));\n"
+                + "  }\n"
+                + "</script>\n"
+                + "</head>\n"
+                + "<body onload='test()'>\n"
+                + "</body></html>";
+
+        loadPageVerifyTitle2(html);
+    }
 }

src/test/java/org/htmlunit/javascript/host/intl/NumberFormatTest.java

@@ -111,4 +111,27 @@ public void numberFormat() throws Exception {
 
         loadPageVerifyTitle2(html);
     }
+
+    /**
+     * @throws Exception if the test fails
+     */
+    @Test
+    @Alerts({"en", "en,ja", ""})
+    public void supportedLocalesOf() throws Exception {
+        final String html = DOCTYPE_HTML
+                + "<html><head>\n"
+                + "<script>\n"
+                + LOG_TITLE_FUNCTION
+                + "  function test() {\n"
+                + "    log(Intl.NumberFormat.supportedLocalesOf('en'));\n"
+                + "    log(Intl.NumberFormat.supportedLocalesOf(['en', 'xx-YY', 'ja']));\n"
+                + "    log(Intl.NumberFormat.supportedLocalesOf([]));\n"
+                + "  }\n"
+                + "</script>\n"
+                + "</head>\n"
+                + "<body onload='test()'>\n"
+                + "</body></html>";
+
+        loadPageVerifyTitle2(html);
+    }
 }