frontend/.prettierignore

@@ -1 +1,2 @@
 src/lib/api.d.ts
+src/i18n/locales/*/*.ts

frontend/.swcrc

@@ -0,0 +1,15 @@
+{
+  "$schema": "https://swc.rs/schema.json",
+  "jsc": {
+    "experimental": {
+      "plugins": [
+        [
+          "@lingui/swc-plugin",
+          {
+            // Additional Configuration
+          }
+        ]
+      ]
+    }
+  }
+}

frontend/README.md

@@ -2,6 +2,63 @@
 
 ## Developing
 
+## i18n
+
+This project uses [Lingui](https://lingui.js.org/) for internalization. The translations are stored in the `src/i18n/locales` folder.
+
+**Translating in JSX: `<Trans>` Component**
+
+Use the `<Trans>` component when translating strings directly in JSX markup:
+
+```jsx
+import { Trans } from "@lingui/react/macro";
+
+function Greeting() {
+  return (
+    <h1>
+      <Trans>Hello, world!</Trans>
+    </h1>
+  );
+}
+```
+
+**Translating in JavaScript: `i18n._(t\`...`)`**
+
+For translations used **outside of JSX**, such as in variables, logs, or logic, use `i18n._(t\`...`)`:
+
+Example:
+
+```jsx
+import { t } from "@lingui/core/macro";
+import { i18n } from "@lingui/core";
+
+console.log(i18n._(t`Operation completed successfully.`));
+```
+
+### Extracting & Compiling Translations
+
+#### Extract Strings
+
+To extract translatable strings into `.po` files:
+
+```bash
+# To extract all translations
+npm run extract
+
+# To extract translations and clean up unused ones
+npm run extract-clean
+```
+
+This updates the `messages.po` files inside `src/i18n/locales/{locale}/`.
+
+#### Compile Translations
+
+After updating the `.po` files with your translations, compile them into `.ts` files:
+
+```bash
+npm run compile
+```
+
 ### Prerequisites
 
 - Node v20

frontend/eslint.config.js

@@ -6,7 +6,7 @@ import tseslint from "typescript-eslint";
 import eslintConfigPrettier from "eslint-config-prettier/flat";
 
 export default tseslint.config(
-  { ignores: ["dist"] },
+  { ignores: ["dist", "src/i18n/locales/**/*.ts"] },
   {
     extends: [
       js.configs.recommended,

frontend/lingui.config.js

@@ -0,0 +1,12 @@
+import { defineConfig } from "@lingui/cli";
+
+export default defineConfig({
+  sourceLocale: "en",
+  locales: ["sv", "en"],
+  catalogs: [
+    {
+      path: "<rootDir>/src/i18n/locales/{locale}/messages",
+      include: ["src"],
+    },
+  ],
+});

frontend/package.json

@@ -5,13 +5,17 @@
   "type": "module",
   "scripts": {
     "dev": "vite",
-    "build": "tsc -b && vite build",
+    "build": "lingui compile --typescript && tsc -b && vite build",
     "lint": "eslint .",
     "format": "prettier . --write",
     "update-api": "openapi-typescript http://localhost:8080/v3/api-docs --output src/lib/api.d.ts",
-    "preview": "vite preview"
+    "preview": "vite preview",
+    "extract": "lingui extract",
+    "extract-clean": "lingui extract --clean",
+    "compile": "lingui compile --typescript"
   },
   "dependencies": {
+    "@lingui/react": "^5.3.0",
     "openapi-fetch": "^0.13.5",
     "react": "^19.0.0",
     "react-dom": "^19.0.0",
@@ -19,6 +23,9 @@
   },
   "devDependencies": {
     "@eslint/js": "^9.21.0",
+    "@lingui/cli": "^5.3.0",
+    "@lingui/swc-plugin": "^5.5.1",
+    "@lingui/vite-plugin": "^5.3.0",
     "@types/react": "^19.0.10",
     "@types/react-dom": "^19.0.4",
     "@vitejs/plugin-react-swc": "^3.8.0",

frontend/src/App.tsx

@@ -3,16 +3,23 @@ import suLogoLandscape from "./assets/SU_logo_optimized.svg";
 import { ProfileContext } from "./hooks/profile.ts";
 import Studentportalen from "./Studentportalen.tsx";
 import { useViewTransitioningFetch } from "./hooks/fetch";
+import { Trans } from "@lingui/react/macro";
+import { useEffect } from "react";
+import { dynamicActivate } from "./i18n/dynamicActivate.ts";
+import { t } from "@lingui/core/macro";
+import { i18n } from "@lingui/core";
 
 function App() {
   const { data: profile, error } = useViewTransitioningFetch("/profile");
 
-  if (!profile) {
-    return splashScreen("Loading...");
-  }
-  if (error) {
-    return splashScreen("Application failed to start");
-  }
+  useEffect(() => {
+    if (profile?.language) {
+      dynamicActivate(profile.language);
+    }
+  }, [profile?.language]);
+
+  if (!profile) return splashScreen(i18n._(t`Loading...`));
+  if (error) return splashScreen(i18n._(t`Application failed to start`));
 
   return (
     <ProfileContext value={profile}>
@@ -23,12 +30,16 @@ function App() {
 
 function splashScreen(extraContent: string) {
   return (
-    <div id={"app"}>
-      <img src={suLogoLandscape} alt={"Stockholm University"} />
+    <div id="app">
+      <img src={suLogoLandscape} alt={i18n._(t`Stockholm University`)} />
       <div>
-        <h1>Student portal</h1>
-        <h2>Department of Computer and Systems Sciences</h2>
-        {extraContent}
+        <h1>
+          <Trans>Student portal</Trans>
+        </h1>
+        <h2>
+          <Trans>Department of Computer and Systems Sciences</Trans>
+        </h2>
+        <p>{extraContent}</p>
       </div>
     </div>
   );

frontend/src/i18n/dynamicActivate.ts

@@ -0,0 +1,12 @@
+import { i18n } from "@lingui/core";
+
+/**
+ * We do a dynamic import of just the catalog that we need.
+ * Source: https://lingui.dev/guides/dynamic-loading-catalogs
+ * @param locale any locale string
+ */
+export async function dynamicActivate(locale: string) {
+  const { messages } = await import(`./locales/${locale}/messages.po`);
+  i18n.load(locale, messages);
+  i18n.activate(locale);
+}

frontend/src/i18n/getDefaultLocale.ts

@@ -0,0 +1,15 @@
+const supportedLocales = ["sv", "en"];
+
+export function getDefaultLocale(): string {
+  const userPreferredLangs = navigator.languages.map(
+    (lang) => lang.split("-")[0],
+  );
+
+  for (const lang of userPreferredLangs) {
+    if (supportedLocales.includes(lang)) {
+      return lang;
+    }
+  }
+
+  return "en"; // fallback to English
+}

frontend/src/i18n/locales/en/messages.po

@@ -0,0 +1,55 @@
+msgid ""
+msgstr ""
+"POT-Creation-Date: 2025-04-07 19:53+0200\n"
+"MIME-Version: 1.0\n"
+"Content-Type: text/plain; charset=utf-8\n"
+"Content-Transfer-Encoding: 8bit\n"
+"X-Generator: @lingui/cli\n"
+"Language: en\n"
+"Project-Id-Version: \n"
+"Report-Msgid-Bugs-To: \n"
+"PO-Revision-Date: \n"
+"Last-Translator: \n"
+"Language-Team: \n"
+"Plural-Forms: \n"
+
+#: src/App.tsx:22
+msgid "Application failed to start"
+msgstr "Application failed to start"
+
+#: src/App.tsx:40
+msgid "Department of Computer and Systems Sciences"
+msgstr "Department of Computer and Systems Sciences"
+
+#: src/studentportalen/Home.tsx:10
+msgid "Here you can see the latest and greatest"
+msgstr "Here you can see the latest and greatest"
+
+#: src/studentportalen/Menu.tsx:12
+msgid "Home"
+msgstr "Home"
+
+#: src/studentportalen/Home.tsx:7
+msgid "Home screen"
+msgstr "Home screen"
+
+#: src/App.tsx:21
+msgid "Loading..."
+msgstr "Loading..."
+
+#: src/studentportalen/Menu.tsx:24
+msgid "Log out"
+msgstr "Log out"
+
+#: src/studentportalen/Menu.tsx:21
+msgid "Profile"
+msgstr "Profile"
+
+#: src/App.tsx:34
+#: src/studentportalen/Header.tsx:12
+msgid "Stockholm University"
+msgstr "Stockholm University"
+
+#: src/App.tsx:37
+msgid "Student portal"
+msgstr "Student portal"

frontend/src/i18n/locales/en/messages.ts

@@ -0,0 +1 @@
+/*eslint-disable*/import type{Messages}from"@lingui/core";export const messages=JSON.parse("{\"3C3CY2\":[\"Application failed to start\"],\"xYQvrP\":[\"Department of Computer and Systems Sciences\"],\"z13C6e\":[\"Here you can see the latest and greatest\"],\"i0qMbr\":[\"Home\"],\"p7H6+B\":[\"Home screen\"],\"Z3FXyt\":[\"Loading...\"],\"FgAxTj\":[\"Log out\"],\"vERlcd\":[\"Profile\"],\"he8WSY\":[\"Stockholm University\"],\"07DTL2\":[\"Student portal\"]}")as Messages;

frontend/src/i18n/locales/sv/messages.po

@@ -0,0 +1,55 @@
+msgid ""
+msgstr ""
+"POT-Creation-Date: 2025-04-07 19:53+0200\n"
+"MIME-Version: 1.0\n"
+"Content-Type: text/plain; charset=utf-8\n"
+"Content-Transfer-Encoding: 8bit\n"
+"X-Generator: @lingui/cli\n"
+"Language: sv\n"
+"Project-Id-Version: \n"
+"Report-Msgid-Bugs-To: \n"
+"PO-Revision-Date: \n"
+"Last-Translator: \n"
+"Language-Team: \n"
+"Plural-Forms: \n"
+
+#: src/App.tsx:22
+msgid "Application failed to start"
+msgstr "Applikationen startade inte"
+
+#: src/App.tsx:40
+msgid "Department of Computer and Systems Sciences"
+msgstr "Institutionen för data- och systemvetenskap"
+
+#: src/studentportalen/Home.tsx:10
+msgid "Here you can see the latest and greatest"
+msgstr "Här kan du hitta det senaste och bästa"
+
+#: src/studentportalen/Menu.tsx:12
+msgid "Home"
+msgstr "Hem"
+
+#: src/studentportalen/Home.tsx:7
+msgid "Home screen"
+msgstr "Hemskärm"
+
+#: src/App.tsx:21
+msgid "Loading..."
+msgstr "Laddar..."
+
+#: src/studentportalen/Menu.tsx:24
+msgid "Log out"
+msgstr "Logga ut"
+
+#: src/studentportalen/Menu.tsx:21
+msgid "Profile"
+msgstr "Profil"
+
+#: src/App.tsx:34
+#: src/studentportalen/Header.tsx:12
+msgid "Stockholm University"
+msgstr "Stockholms universitet"
+
+#: src/App.tsx:37
+msgid "Student portal"
+msgstr "Studentportal"

frontend/src/i18n/locales/sv/messages.ts

@@ -0,0 +1 @@
+/*eslint-disable*/import type{Messages}from"@lingui/core";export const messages=JSON.parse("{\"3C3CY2\":[\"Applikationen startade inte\"],\"xYQvrP\":[\"Institutionen för data- och systemvetenskap\"],\"z13C6e\":[\"Här kan du hitta det senaste och bästa\"],\"i0qMbr\":[\"Hem\"],\"p7H6+B\":[\"Hemskärm\"],\"Z3FXyt\":[\"Laddar...\"],\"FgAxTj\":[\"Logga ut\"],\"vERlcd\":[\"Profil\"],\"he8WSY\":[\"Stockholms universitet\"],\"07DTL2\":[\"Studentportal\"]}")as Messages;

frontend/src/main.tsx

@@ -2,9 +2,19 @@ import { StrictMode } from "react";
 import { createRoot } from "react-dom/client";
 import "./index.css";
 import App from "./App.tsx";
+import { I18nProvider } from "@lingui/react";
+import { i18n } from "@lingui/core";
+import { dynamicActivate } from "./i18n/dynamicActivate.ts";
+import { getDefaultLocale } from "./i18n/getDefaultLocale.ts";
+
+// Activate the default locale from browser settings before a profile is loaded
+const locale = getDefaultLocale();
+await dynamicActivate(locale);
 
 createRoot(document.getElementById("root")!).render(
   <StrictMode>
-    <App />
+    <I18nProvider i18n={i18n}>
+      <App />
+    </I18nProvider>
   </StrictMode>,
 );

frontend/src/studentportalen/Header.tsx

@@ -1,13 +1,16 @@
 import "./header.css";
 import suLogo from "../assets/SU_logo_optimized.svg";
 import { useProfile } from "../hooks/profile.ts";
+import { t } from "@lingui/core/macro";
+import { i18n } from "@lingui/core";
 
 export default function Header() {
   const profile = useProfile();
 
   return (
     <header>
-      <img src={suLogo} alt="Stockholm University" />
+      <img src={suLogo} alt={i18n._(t`Stockholm University`)} />
+
       <span>{profile.name}</span>
     </header>
   );

frontend/src/studentportalen/Home.tsx

@@ -1,8 +1,14 @@
+import { Trans } from "@lingui/react/macro";
+
 export default function Home() {
   return (
     <>
-      <h1>Home screen</h1>
-      <p>Here you can see the latest and greatest</p>
+      <h1>
+        <Trans>Home screen</Trans>
+      </h1>
+      <p>
+        <Trans>Here you can see the latest and greatest</Trans>
+      </p>
     </>
   );
 }

frontend/src/studentportalen/Menu.tsx

@@ -1,21 +1,28 @@
 import { NavLink } from "react-router";
 import "./menu.css";
 import { useState } from "react";
+import { Trans } from "@lingui/react/macro";
 
 export default function Menu() {
   const [subMenuVisible, setSubMenuVisible] = useState(false);
   return (
     <menu className={"main"}>
       <li>
-        <NavLink to={"/"}>Home</NavLink>
+        <NavLink to={"/"}>
+          <Trans>Home</Trans>
+        </NavLink>
       </li>
       <li>
         <button onClick={() => setSubMenuVisible((current) => !current)}>
           <span>| | |</span>
         </button>
         <menu className={"sub " + (subMenuVisible ? "visible" : "")}>
-          <li>Profile</li>
-          <li>Log out</li>
+          <li>
+            <Trans>Profile</Trans>
+          </li>
+          <li>
+            <Trans>Log out</Trans>
+          </li>
         </menu>
       </li>
     </menu>

frontend/vite.config.ts

@@ -1,7 +1,15 @@
 import { defineConfig } from "vite";
 import react from "@vitejs/plugin-react-swc";
+import { lingui } from "@lingui/vite-plugin";
 
-// https://vite.dev/config/
 export default defineConfig({
-  plugins: [react()],
+  build: {
+    target: "esnext",
+  },
+  plugins: [
+    react({
+      plugins: [["@lingui/swc-plugin", {}]],
+    }),
+    lingui(),
+  ],
 });