Refactor (packages/web/src/i18n/locales.ts): Function with many returns

packages/web/package.json

@@ -9,7 +9,8 @@
     "start": "astro dev",
     "build": "astro build",
     "preview": "astro preview",
-    "astro": "astro"
+    "astro": "astro",
+    "test": "bun test"
   },
   "dependencies": {
     "@astrojs/cloudflare": "12.6.3",
@@ -41,4 +42,4 @@
     "@astrojs/check": "0.9.6",
     "typescript": "catalog:"
   }
-}
+}

packages/web/src/i18n/locales.ts

@@ -99,19 +99,20 @@ export function matchLocale(input: string) {
   const value = parse(input)
   if (!value) return null
 
-  if (value.startsWith("zh")) {
-    if (value.includes("hant") || value.includes("-tw") || value.includes("-hk") || value.includes("-mo")) {
-      return "zh-tw"
-    }
-    return "zh-cn"
-  }
+  let match: Locale | null = starts.find((item) => value.startsWith(item[0]))?.[1] ?? null
 
-  if (value in localeAlias) {
-    return localeAlias[value as keyof typeof localeAlias]
+  if (value.startsWith("zh")) {
+    match =
+      value.includes("hant") || value.includes("-tw") || value.includes("-hk") || value.includes("-mo")
+        ? "zh-tw"
+        : "zh-cn"
+  } else if (value in localeAlias) {
+    match = localeAlias[value as keyof typeof localeAlias]
+  } else if (value.startsWith("pt")) {
+    match = "pt-br"
+  } else if (value.startsWith("no") || value.startsWith("nb") || value.startsWith("nn")) {
+    match = "nb"
   }
 
-  if (value.startsWith("pt")) return "pt-br"
-  if (value.startsWith("no") || value.startsWith("nb") || value.startsWith("nn")) return "nb"
-
-  return starts.find((item) => value.startsWith(item[0]))?.[1] ?? null
+  return match
 }

packages/web/test/locales.test.ts

@@ -0,0 +1,23 @@
+import { describe, expect, test } from "bun:test"
+import { matchLocale } from "../src/i18n/locales"
+
+describe("matchLocale", () => {
+    test("matches exact and prefixed locales", () => {
+        expect(matchLocale("de")).toBe("de")
+        expect(matchLocale("fr-CA")).toBe("fr")
+        expect(matchLocale("pt-PT")).toBe("pt-br")
+        expect(matchLocale("nn-NO")).toBe("nb")
+    })
+
+    test("matches Chinese locale variants", () => {
+        expect(matchLocale("zh-Hant")).toBe("zh-tw")
+        expect(matchLocale("zh-TW")).toBe("zh-tw")
+        expect(matchLocale("zh-CN")).toBe("zh-cn")
+    })
+
+    test("returns null for invalid or unsupported locales", () => {
+        expect(matchLocale("")).toBeNull()
+        expect(matchLocale("%")).toBeNull()
+        expect(matchLocale("unsupported")).toBeNull()
+    })
+})