fix: handle undefined return values in parseRetryAfter function

Author: pelikhan

packages/core/src/fetch.ts

@@ -114,7 +114,7 @@ export async function createFetch(
     maxDelay = FETCH_RETRY_MAX_DELAY_DEFAULT,
     maxRetryAfter = FETCH_RETRY_MAX_RETRY_AFTER_DEFAULT,
     cancellationToken,
-  } = options;
+  } = options || {};
   const minDelay = FETCH_RETRY_MIN_DELAY_DEFAULT;
 
   dbg(`create fetch`);

packages/core/test/fetch-retry-after.test.ts

@@ -22,13 +22,13 @@ describe("parseRetryAfter", () => {
   });
 
   test("handles invalid input", () => {
-    assert.strictEqual(parseRetryAfter(""), null);
-    assert.strictEqual(parseRetryAfter("invalid"), null);
-    assert.strictEqual(parseRetryAfter("not-a-date"), null);
+    assert.strictEqual(parseRetryAfter(""), undefined);
+    assert.strictEqual(parseRetryAfter("invalid"), undefined);
+    assert.strictEqual(parseRetryAfter("not-a-date"), undefined);
   });
 
   test("handles negative seconds", () => {
-    assert.strictEqual(parseRetryAfter("-10"), null);
+    assert.strictEqual(parseRetryAfter("-10"), undefined);
   });
 
   test("handles past dates", () => {