fixing telegram provider not respecting rate limits

lib/notification/adapter/telegram.js

@@ -2,6 +2,8 @@ const { markdown2Html } = require('../../services/markdown');
 const { getJob } = require('../../services/storage/jobStorage');
 const axios = require('axios');
 
+const MAX_ENTITIES_PER_CHUNK = 8;
+const RATE_LIMIT_INTERVAL = 1010;
 /**
  * splitting an array into chunks because Telegram only allows for messages up to
  * 4096 chars, thus we have to split messages into chunks
@@ -29,7 +31,7 @@ exports.send = ({ serviceName, newListings, notificationConfig, jobKey }) => {
   const jobName = job == null ? jobKey : job.name;
 
   //we have to split messages into chunk, because otherwise messages are going to become too big and will fail
-  const chunks = arrayChunks(newListings, 3);
+  const chunks = arrayChunks(newListings, MAX_ENTITIES_PER_CHUNK);
 
   const promises = chunks.map((chunk) => {
     let message = `<i>${jobName}</i> (${serviceName}) found <b>${newListings.length}</b> new listings:\n\n`;
@@ -40,11 +42,21 @@ exports.send = ({ serviceName, newListings, notificationConfig, jobKey }) => {
         '\n\n'
     );
 
-    return axios.post(`https://api.telegram.org/bot${token}/sendMessage`, {
-      chat_id: chatId,
-      text: message,
-      parse_mode: 'HTML',
-      disable_web_page_preview: true,
+    /**
+     * This is to not break the rate limit. It is to only send 1 message per second
+     */
+    return new Promise((resolve, reject) => {
+      setTimeout(() => {
+        axios
+          .post(`https://api.telegram.org/bot${token}/sendMessage`, {
+            chat_id: chatId,
+            text: message,
+            parse_mode: 'HTML',
+            disable_web_page_preview: true,
+          })
+          .then(() => resolve())
+          .catch(() => reject());
+      }, RATE_LIMIT_INTERVAL);
     });
   });