chore: cache heartbeats request when they fail or users are offline

src/background.ts

@@ -1,11 +1,32 @@
 import browser from 'webextension-polyfill';
 import WakaTimeCore from './core/WakaTimeCore';
 
+// Add a listener to resolve alarms
+browser.alarms.onAlarm.addListener(async (alarm) => {
+  // |alarm| can be undefined because onAlarm also gets called from
+  // window.setTimeout on old chrome versions.
+  // eslint-disable-next-line @typescript-eslint/no-unnecessary-condition
+  if (alarm && alarm.name == 'heartbeatAlarm') {
+    // Checks if the user is online and if there are cached heartbeats requests,
+    // if so then procedd to send these payload to wakatime api
+    if (navigator.onLine) {
+      const { cachedHeartbeats } = await browser.storage.sync.get({
+        cachedHeartbeats: [],
+      });
+      await browser.storage.sync.set({ cachedHeartbeats: [] });
+      await WakaTimeCore.sendCachedHeartbeatsRequest(cachedHeartbeats as Record<string, unknown>[]);
+    }
+  }
+});
+
+// Create a new alarm for sending cached heartbeats.
+browser.alarms.create('heartbeatAlarm', { periodInMinutes: 2 });
+
 /**
  * Whenever a active tab is changed it records a heartbeat with that tab url.
  */
 browser.tabs.onActivated.addListener(async () => {
-  console.log('recording a heartbeat - active tab changed');
+  console.log('recording a heartbeat - active tab changed ');
   await WakaTimeCore.recordHeartbeat();
 });
 

src/core/WakaTimeCore.ts

@@ -262,9 +262,44 @@ class WakaTimeCore {
       const data = await response.json();
       return data;
     } catch (err: unknown) {
+      // Stores the payload of the request to be send later
+      const { cachedHeartbeats } = await browser.storage.sync.get({
+        cachedHeartbeats: [],
+      });
+      cachedHeartbeats.push(payload);
+      await browser.storage.sync.set({ cachedHeartbeats });
       await changeExtensionState('notSignedIn');
     }
   }
+
+  /**
+   * Sends cached heartbeats request to wakatime api
+   * @param requests
+   */
+  async sendCachedHeartbeatsRequest(requests: Record<string, unknown>[]): Promise<void> {
+    const apiKey = await this.getApiKey();
+    if (!apiKey) {
+      return changeExtensionState('notLogging');
+    }
+    const chunkSize = 50; // Create batches of max 50 request
+    for (let i = 0; i < requests.length; i += chunkSize) {
+      const chunk = requests.slice(i, i + chunkSize);
+      const requestsPromises: Promise<Response>[] = [];
+      chunk.forEach((request) =>
+        requestsPromises.push(
+          fetch(`${config.heartbeatApiUrl}?api_key=${apiKey}`, {
+            body: JSON.stringify(request),
+            method: 'POST',
+          }),
+        ),
+      );
+      try {
+        await Promise.all(requestsPromises);
+      } catch (error: unknown) {
+        console.log('Error sending heartbeats');
+      }
+    }
+  }
 }
 
 export default new WakaTimeCore();