feat: add localeAlias options

index.js

@@ -24,6 +24,7 @@ const DEFAULT_OPTIONS = {
   defaultLocale: 'en-US',
   queryField: 'locale',
   cookieField: 'locale',
+  localeAlias: {},
   cookieMaxAge: '1y',
   dir: undefined,
   dirs: [path.join(process.cwd(), 'locales')],
@@ -35,6 +36,7 @@ module.exports = function (app, options) {
   const defaultLocale = formatLocale(options.defaultLocale);
   const queryField = options.queryField;
   const cookieField = options.cookieField;
+  const localeAlias = options.localeAlias;
   const cookieMaxAge = ms(options.cookieMaxAge);
   const localeDir = options.dir;
   const localeDirs = options.dirs;
@@ -172,6 +174,9 @@ module.exports = function (app, options) {
       }
     }
 
+    // cookie alias
+    if (locale in localeAlias) locale = localeAlias[locale];
+
     locale = formatLocale(locale);
 
     // validate locale