From 3e47e5a8424d9e84f9bc102cb0b7205845b28263 Mon Sep 17 00:00:00 2001
From: ShafinNigamana <shafin.nigamana@gmail.com>
Date: Fri, 12 Jun 2026 01:25:02 +0530
Subject: [PATCH] \test(cacheControl): add empty-fallback test and robust
 options parameter handling"

---
 utils/cacheControl.empty-fallback.test.ts | 59 +++++++++++++++++++++++
 utils/cacheControl.ts                     |  9 ++--
 2 files changed, 62 insertions(+), 6 deletions(-)
 create mode 100644 utils/cacheControl.empty-fallback.test.ts

diff --git a/utils/cacheControl.empty-fallback.test.ts b/utils/cacheControl.empty-fallback.test.ts
new file mode 100644
index 000000000..b8d763102
--- /dev/null
+++ b/utils/cacheControl.empty-fallback.test.ts
@@ -0,0 +1,59 @@
+/* eslint-disable @typescript-eslint/no-explicit-any */
+import { describe, expect, it } from 'vitest';
+import { buildCacheControlHeader } from './cacheControl';
+
+describe('buildCacheControlHeader - Edge Cases & Empty/Missing Inputs Verification', () => {
+  it('1. falls back to default cache control when options object is completely omitted', () => {
+    // Calling the function with no arguments should fallback gracefully without throwing
+    expect(buildCacheControlHeader()).toBe('s-maxage=3600, stale-while-revalidate=86400');
+  });
+
+  it('2. falls back to default cache control when options is an empty object', () => {
+    expect(buildCacheControlHeader({})).toBe('s-maxage=3600, stale-while-revalidate=86400');
+  });
+
+  it('3. falls back to default cache control when options object is null', () => {
+    // Casting to any to test JavaScript-level null input resilience
+    expect(buildCacheControlHeader(null as any)).toBe(
+      's-maxage=3600, stale-while-revalidate=86400'
+    );
+  });
+
+  it('4. falls back to default cache control when options contain only undefined or null values', () => {
+    expect(
+      buildCacheControlHeader({
+        bypass: undefined,
+        secondsToMidnight: undefined,
+        isHistoricalYear: undefined,
+      })
+    ).toBe('s-maxage=3600, stale-while-revalidate=86400');
+
+    expect(
+      buildCacheControlHeader({
+        bypass: null as any,
+        secondsToMidnight: null as any,
+        isHistoricalYear: null as any,
+      })
+    ).toBe('s-maxage=3600, stale-while-revalidate=86400');
+  });
+
+  it('5. prioritizes bypass=true even if other options are invalid/null/undefined', () => {
+    expect(
+      buildCacheControlHeader({
+        bypass: true,
+        secondsToMidnight: null as any,
+        isHistoricalYear: undefined,
+      })
+    ).toBe('no-cache, no-store, must-revalidate');
+  });
+
+  it('6. prioritizes isHistoricalYear=true when bypass is falsy and secondsToMidnight is null/undefined', () => {
+    expect(
+      buildCacheControlHeader({
+        bypass: false,
+        secondsToMidnight: undefined,
+        isHistoricalYear: true,
+      })
+    ).toBe('public, s-maxage=31536000, immutable');
+  });
+});
diff --git a/utils/cacheControl.ts b/utils/cacheControl.ts
index 2972cb658..05d95ce2f 100644
--- a/utils/cacheControl.ts
+++ b/utils/cacheControl.ts
@@ -4,11 +4,8 @@ interface CacheControlOptions {
   isHistoricalYear?: boolean;
 }
 
-export function buildCacheControlHeader({
-  bypass,
-  secondsToMidnight,
-  isHistoricalYear,
-}: CacheControlOptions): string {
+export function buildCacheControlHeader(options: CacheControlOptions = {}): string {
+  const { bypass, secondsToMidnight, isHistoricalYear } = options || {};
   if (bypass) {
     return 'no-cache, no-store, must-revalidate';
   }
@@ -17,7 +14,7 @@ export function buildCacheControlHeader({
     return 'public, s-maxage=31536000, immutable';
   }
 
-  if (secondsToMidnight !== undefined) {
+  if (secondsToMidnight !== undefined && secondsToMidnight !== null) {
     return `public, s-maxage=${secondsToMidnight}, stale-while-revalidate=86400`;
   }