fix(Intl): fall back to ISO language 2-code name when the expanded va…

…riant isn't available

src/service/polyfill-builder/polyfill-builder-service.ts

@@ -10,21 +10,6 @@ import {IPolyfillDictEntryBase} from "../../polyfill/polyfill-dict";
 import {PolyfillContext} from "../../polyfill/polyfill-context";
 import {IPolyfillRequest} from "../../polyfill/i-polyfill-request";
 
-function normalizeIntlLocale(locale: string): string {
-	const localeData = new (Intl as any).Locale(locale);
-	switch (localeData.basename) {
-		case "pt-BR":
-			// @formatjs does not provide data for brazilian Portuguese,
-			// so we'll have to fall back to the base language here
-			// TODO: Remove this when @formatjs eventually supports pt-BR.
-			//       Track this issue: https://github.com/formatjs/formatjs/issues/2237
-			return localeData.language;
-		default:
-			// For all other languages, use the base name
-			return localeData.basename;
-	}
-}
-
 const SYNC_OPTIONS = {cwd: __dirname};
 
 function selectMetaPaths<Meta extends Exclude<IPolyfillDictEntryBase["meta"], undefined>>(value: Meta[keyof Meta], context: PolyfillContext): string[] {
@@ -206,12 +191,20 @@ export class PolyfillBuilderService implements IPolyfillBuilderService {
 					requestedLocales.map(async requestedLocale => {
 						// Resolve the absolute path
 						for (const localeDir of selectMetaPaths(meta.localeDir, request.context)) {
-							const localePathInput = join(rootDirectory, localeDir, `${normalizeIntlLocale(requestedLocale)}.js`);
-							const resolvedLocalePath = sync(localePathInput, SYNC_OPTIONS);
-							if (resolvedLocalePath != null) {
-								absolutePaths.push(resolvedLocalePath);
-							} else {
-								throw new ReferenceError(`Unresolved path: '${localePathInput}'`);
+							const locale = new (Intl as any).Locale(requestedLocale);
+							let addedLocale = false;
+							for (const currentLocale of [locale.baseName, locale.language]) {
+								const localePathInput = join(rootDirectory, localeDir, `${currentLocale}.js`);
+								const resolvedLocalePath = sync(localePathInput, SYNC_OPTIONS);
+								if (resolvedLocalePath != null) {
+									addedLocale = true;
+									absolutePaths.push(resolvedLocalePath);
+									break;
+								}
+							}
+
+							if (!addedLocale) {
+								throw new ReferenceError(`Unresolved locale: '${requestedLocale}'`);
 							}
 						}
 					})