fix(validation): validate lang parameter against supported languages

Author: Thacker-Meet

lib/i18n/badgeLabels.ts

@@ -72,6 +72,11 @@ export const labels: Record<string, BadgeLabels> = {
   },
 };
 
+export const supportedLanguages = Object.keys(labels) as [
+  keyof typeof labels,
+  ...(keyof typeof labels)[],
+];
+
 export function getLabels(lang: string = 'en'): BadgeLabels {
   return labels[lang.toLowerCase()] || labels['en'];
 }

lib/validations.ts

@@ -1,5 +1,5 @@
 // lib/validations.ts
-
+import { supportedLanguages } from './i18n/badgeLabels';
 import { z } from 'zod';
 import {
   isValidHex,
@@ -173,7 +173,7 @@ export const streakParamsSchema = z.object({
   hide_title: z.string().optional().transform(toBooleanFlag),
   hide_background: z.string().optional().transform(toBooleanFlag),
   hide_stats: z.string().optional().transform(toBooleanFlag),
-  lang: z.string().optional().default('en'),
+  lang: z.enum(supportedLanguages).catch('en').default('en'),
   // Unknown view values fall back to the default dashboard view.
   view: z.enum(['default', 'monthly']).catch('default').default('default'),
   // Invalid delta formats fall back to percentage mode.