stevekrouse · February 16, 2025 00:11 · Feb 16, 2025
diff --git a/gistfile1.txt b/gistfile1.txt
@@ -0,0 +1,91 @@
+Find the bug
+
+import { email } from "https://esm.town/v/std/email?v=13";
+const MAX_TRIES = 3;
+export async function uptimeCheck(url: string, attempt = 1) {
+  let ok = true;
+  try {
+    const res = await fetch(url);
+    if (res.status === 200) {
+      console.log(`Website up (${url})`);
+    } else {
+      ok = false;
+    }
+  } catch (e) {
+    ok = false;
+  }
+  if (!ok) {
+    if (attempt < MAX_TRIES) {
+      console.log(`${url} down, attempt ${attempt}, retrying...`);
+      return uptimeCheck(url, attempt + 1);
+    } else {
+      console.log(`${url} down, attempt ${attempt}, notifying...`);
+      await email({ subject: `Website down (${url})` });
+    }
+  }
+}
+const urls = [
+  "https://www.google.com",
+  "https://www.youtube.com",
+  "https://www.biasdfafng.com",
+];
+await Promise.all(
+  urls.map(uptimeCheck),
+);
+
+=====================
+
+There's a bug in how the function handles the return value during recursive retries. Here's the issue and fix:
+
+The function doesn't return a value in the success case (when `ok` is true), which means it returns `undefined`. In the retry case, while it returns the recursive call to `uptimeCheck`, this value isn't being used or propagated up.
+
+Here's the corrected version:
+
+```typescript
+import { email } from "https://esm.town/v/std/email?v=13";
+const MAX_TRIES = 3;
+
+export async function uptimeCheck(url: string, attempt = 1) {
+  let ok = true;
+  try {
+    const res = await fetch(url);
+    if (res.status === 200) {
+      console.log(`Website up (${url})`);
+      return true; // Add explicit return for success case
+    } else {
+      ok = false;
+    }
+  } catch (e) {
+    ok = false;
+  }
+
+  if (!ok) {
+    if (attempt < MAX_TRIES) {
+      console.log(`${url} down, attempt ${attempt}, retrying...`);
+      return uptimeCheck(url, attempt + 1);
+    } else {
+      console.log(`${url} down, attempt ${attempt}, notifying...`);
+      await email({ subject: `Website down (${url})` });
+      return false; // Add explicit return for failure case
+    }
+  }
+}
+
+const urls = [
+  "https://www.google.com",
+  "https://www.youtube.com", 
+  "https://www.biasdfafng.com",
+];
+
+await Promise.all(
+  urls.map(uptimeCheck),
+);
+```
+
+The main changes made:
+1. Added `return true` in the success case when status is 200
+2. Added `return false` after sending the email in the failure case
+
+Without these explicit returns, the function could return `undefined` in some cases, which makes it harder to track the actual status of each check. Now the function will consistently return a boolean indicating whether the check ultimately succeeded or failed.
+
+This is important because Promise.all() is being used to run these checks in parallel, and having proper return values makes it easier to handle and track the results if needed.