diff --git a/src/components/About.astro b/src/components/About.astro
index 0f9fc5a..2b90f5b 100644
--- a/src/components/About.astro
+++ b/src/components/About.astro
@@ -1,8 +1,8 @@
 ---
-import { translations } from '@data/i18n.js';
+import { translations, type Lang } from '@data/i18n';
 import { Image } from 'astro:assets';
 import benker from '@assets/studioBenker.png';
-const { lang = 'no' } = Astro.props;
+const { lang = 'no' } = Astro.props as { lang?: Lang };
 const t = translations[lang].about;
 ---
 
diff --git a/src/components/FAQ.astro b/src/components/FAQ.astro
index 5f1f0d9..906eae5 100644
--- a/src/components/FAQ.astro
+++ b/src/components/FAQ.astro
@@ -1,6 +1,6 @@
 ---
-import { translations } from '@data/i18n.js';
-const { lang = 'no' } = Astro.props;
+import { translations, type Lang } from '@data/i18n';
+const { lang = 'no' } = Astro.props as { lang?: Lang };
 const t = translations[lang].faq;
 ---
 
diff --git a/src/components/Footer.astro b/src/components/Footer.astro
index fb63986..c29d811 100644
--- a/src/components/Footer.astro
+++ b/src/components/Footer.astro
@@ -2,9 +2,9 @@
 import { Image } from 'astro:assets';
 import logo from '@assets/logo.png';
 import DNS  from '@assets/DNS-logo-hvit.png';
-import { translations } from '@data/i18n.js';
+import { translations, type Lang } from '@data/i18n';
 import Links from '@components/Links.astro';
-const { lang = 'no' } = Astro.props;
+const { lang = 'no' } = Astro.props as { lang?: Lang };
 const t = translations[lang].footer;
 ---
 
diff --git a/src/components/Hero.astro b/src/components/Hero.astro
index 54769bf..e018644 100644
--- a/src/components/Hero.astro
+++ b/src/components/Hero.astro
@@ -1,8 +1,8 @@
 ---
 import logo from '@assets/logo.png';
 import { Image } from 'astro:assets';
-import { translations } from '@data/i18n.js';
-const { lang = 'no' } = Astro.props;
+import { translations, type Lang } from '@data/i18n';
+const { lang = 'no' } = Astro.props as { lang?: Lang };
 const t = translations[lang].hero;
 ---
 
diff --git a/src/components/Nav.astro b/src/components/Nav.astro
index 8d7e4c2..6f38e70 100644
--- a/src/components/Nav.astro
+++ b/src/components/Nav.astro
@@ -1,12 +1,11 @@
 ---
 import NavLink from '@components/NavLink.astro';
-
-import { translations } from '@data/i18n.js';
-const { lang = 'no' } = Astro.props;
+import { translations, type Lang } from '@data/i18n';
+const { lang = 'no' } = Astro.props as { lang?: Lang };
 const t = translations[lang].nav;
 const { pathname } = Astro.url;
 
-function getLangSwitchPath(path, lang) {
+function getLangSwitchPath(path: string, lang: string) {
   if (lang === 'no') {
     if (path === '/') return '/en/';
     if (path.startsWith('/en/')) return path.replace('/en/', '/');
diff --git a/src/components/Program.astro b/src/components/Program.astro
index b5f1d92..9c345af 100644
--- a/src/components/Program.astro
+++ b/src/components/Program.astro
@@ -1,9 +1,17 @@
 ---
-import { translations } from '@data/i18n.js';
-const { lang = 'no', data } = Astro.props;
+import { translations, type Lang } from '@data/i18n';
+const { lang = 'no', data } = Astro.props as { lang?: Lang, data: any };
 const t = translations[lang].program;
 
-const convertDate = (date) => {
+type ProgramItem = {
+  time: string;
+  event: string;
+  price?: string | null;
+  cost?: string | null;
+  url?: string;
+};
+
+const convertDate = (date: string | Date) => {
   let d = date;
   if (!(d instanceof Date)) {
     d = new Date(d);
@@ -26,7 +34,7 @@ const convertDate = (date) => {
       <div id="program-list" class="w-125 p-6 border-1 border-white rounded-2xl even:bg-slottsblaa even:text-white bg-gyllen-beige flex flex-col gap-2">
         <h2 class="font-bold text-xl">{convertDate(date)}</h2>
         <ul>
-          {items.map((item) => {
+          {(items as ProgramItem[]).map((item) => {
             const price = item.price || item.cost;
             return (
               <li class="flex justify-between">
diff --git a/src/components/Vors.astro b/src/components/Vors.astro
index 6c831ff..3bb22bc 100644
--- a/src/components/Vors.astro
+++ b/src/components/Vors.astro
@@ -1,6 +1,6 @@
 ---
-import { translations } from '@data/i18n.js';
-const { lang = 'no' } = Astro.props;
+import { translations, type Lang } from '@data/i18n';
+const { lang = 'no' } = Astro.props as { lang?: Lang };
 const t = translations[lang].vors;
 
 const videoUrl = "https://www.youtube.com/watch?v=t7T4RPBpTVY";
diff --git a/src/data/i18n.js b/src/data/i18n.ts
similarity index 98%
rename from src/data/i18n.js
rename to src/data/i18n.ts
index 3a7b8af..9cf767f 100644
--- a/src/data/i18n.js
+++ b/src/data/i18n.ts
@@ -93,4 +93,6 @@ export const translations = {
       dnsAlt: "Logo for the Norwegian Student Society",
     },
   },
-};
+} as const;
+
+export type Lang = keyof typeof translations;