core: fix #483

packages/hydrooj/src/lib/i18n.ts

@@ -42,14 +42,14 @@ String.prototype.translate = function translate(...languages: string[]) {
     if (languages[0]?.startsWith('en')) {
         // For most use cases, source text equals to translated text in English.
         // So if it doesn't exist, we should use the original text instead of fallback.
-        return app.i18n.get(this, languages[0]) || app.i18n.get(this, 'en') || this;
+        return app.i18n.get(this, languages[0]) || app.i18n.get(this, 'en') || this.toString();
     }
     for (const language of languages.filter(Boolean)) {
         const curr = app.i18n.get(this, language) || app.i18n.get(this, language.split('_')[0])
             || app.i18n.get(this, language.split('-')[0]);
         if (curr) return curr;
     }
-    return this;
+    return this.toString();
 };
 
 /** @deprecated use ctx.i18n.load instead. */