vercel-labs
diff --git a/‎lib/cron.ts
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+3Lines changed: 3 additions & 0 deletions b/‎lib/cron.ts
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+3Lines changed: 3 additions & 0 deletions
diff --git a/‎lib/upstash.ts
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+8Lines changed: 8 additions & 0 deletions b/‎lib/upstash.ts
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+8Lines changed: 8 additions & 0 deletions
@@ -2,6 +2,7 @@ import { getLatestPost, getPost } from "./hn";
 import {
   getLastCheckedId,
   setLastCheckedId,
+  checkIfPostWasChecked,
   getTeamsAndKeywords,
 } from "./upstash";
 import { equalsIgnoreOrder, postScanner } from "./helpers";
@@ -28,6 +29,8 @@ export async function cron() {
   let errors: any[] = [];
 
   for (let i = lastCheckedId + 1; i <= latestPostId; i++) {
+    if (await checkIfPostWasChecked(i)) continue; // avoid double checking posts
+
     const post = await getPost(i); // get post from hacker news
     if (!post) {
       console.log(`Hacker News post not found. Post number: ${i}`); // by the off chance that the post fails to fetch/doesn't exist, log it
 
@@ -112,6 +112,14 @@ export async function setLastCheckedId(id: number) {
   return await redis.set("lastCheckedId", id);
 }
 
+export async function checkIfPostWasChecked(id: number) {
+  /* Check if a post has been checked in redis – if setting the key for the post returns null, it means it's already been set */
+  return (
+    (await redis.set(`post_${id}`, true, { nx: true, ex: 24 * 60 * 60 })) ===
+    null
+  );
+}
+
 export interface TeamAndKeywords {
   [teamId: string]: string[];
 }