chore: add inline documentation

Author: saikumarrs

packages/analytics-js-plugins/src/utilities/retryQueue/RetryQueue.ts

@@ -569,13 +569,18 @@ class RetryQueue implements IQueue<QueueItemData> {
         const firstAttemptedAt = inProgressItem?.firstAttemptedAt ?? now;
         const lastAttemptedAt = inProgressItem?.lastAttemptedAt ?? now;
 
-        // A decimal integer representing the seconds since the last attempt
+        // A decimal integer representing the seconds since the first attempt
         const timeSinceFirstAttempt = Math.round((now - firstAttemptedAt) / 1000);
+
+        // A decimal integer representing the seconds since the last attempt
         const timeSinceLastAttempt = Math.round((now - lastAttemptedAt) / 1000);
+
+        // Indicates if the item has been reclaimed from local storage
         const reclaimed = inProgressItem?.reclaimed ?? false;
 
-        // Update the last attempted at timestamp for the in progress item
+        // Update the first attempted at timestamp for the in progress item
         inProgressItem.firstAttemptedAt = firstAttemptedAt;
+        // Update the last attempted at to current timestamp for the in progress item
         inProgressItem.lastAttemptedAt = now;
 
         inProgress[el.id] = inProgressItem;
@@ -669,6 +674,7 @@ class RetryQueue implements IQueue<QueueItemData> {
             type: el.type ?? type,
             firstAttemptedAt: el.firstAttemptedAt,
             lastAttemptedAt: el.lastAttemptedAt,
+            // Mark the item as reclaimed from local storage
             reclaimed: true,
           });
           trackMessageIds.push(id);
@@ -695,6 +701,7 @@ class RetryQueue implements IQueue<QueueItemData> {
           this.enqueue({
             ...el,
             id,
+            // Mark the item as reclaimed from local storage
             reclaimed: true,
             type: el.type ?? SINGLE_QUEUE_ITEM_TYPE,
             time: this.schedule.now(),

packages/analytics-js-plugins/src/xhrQueue/utilities.ts

@@ -93,16 +93,25 @@ const getRequestInfo = (
     url = eventUrl;
   }
 
-  // Add sentAt header
+  // Add current timestamp as sentAt header
+  // The same value is added in the event payload as well
   headers.SentAt = currentTime;
+
+  // Add a header to indicate if the item has been reclaimed from
+  // local storage
   if (qItemProcessInfo.reclaimed) {
     headers.Reclaimed = 'true';
   }
 
-  // Add retry headers if the item is being retried
+  // Add retry headers if the item is being retried for delivery
   if (qItemProcessInfo.retryAttemptNumber > 0) {
+    // The number of times this item has been attempted to retry
     headers['Retry-Attempt'] = qItemProcessInfo.retryAttemptNumber.toString();
+
+    // The number of seconds since the last attempt
     headers['Retried-After'] = qItemProcessInfo.timeSinceLastAttempt.toString();
+
+    // The number of seconds since the first attempt
     headers['Retried-After-First'] = qItemProcessInfo.timeSinceFirstAttempt.toString();
   }