[PM-6426] Implementing methodology for having a fallback to setTimeout if the browser context is lost in some manner

apps/browser/src/platform/services/browser-task-scheduler.service.spec.ts

@@ -80,23 +80,6 @@ describe("BrowserTaskSchedulerService", () => {
   });
 
   describe("setTimeout", () => {
-    it("uses the global setTimeout API if the delay is less than 1000ms", async () => {
-      const delayInMs = 999;
-      jest.spyOn(globalThis, "setTimeout");
-
-      await browserTaskSchedulerService.setTimeout(
-        ScheduledTaskNames.loginStrategySessionTimeout,
-        delayInMs,
-      );
-
-      expect(globalThis.setTimeout).toHaveBeenCalledWith(expect.any(Function), delayInMs);
-      expect(chrome.alarms.create).not.toHaveBeenCalledWith(
-        ScheduledTaskNames.loginStrategySessionTimeout,
-        { delayInMinutes: 1 },
-        expect.any(Function),
-      );
-    });
-
     it("creates a timeout alarm", async () => {
       await browserTaskSchedulerService.setTimeout(
         ScheduledTaskNames.loginStrategySessionTimeout,
@@ -142,5 +125,22 @@ describe("BrowserTaskSchedulerService", () => {
         expect.any(Function),
       );
     });
+
+    it("uses the global setTimeout API if the delay is less than 1000ms", async () => {
+      const delayInMs = 15000;
+      jest.spyOn(globalThis, "setTimeout");
+
+      await browserTaskSchedulerService.setTimeout(
+        ScheduledTaskNames.loginStrategySessionTimeout,
+        delayInMs,
+      );
+
+      expect(globalThis.setTimeout).toHaveBeenCalledWith(expect.any(Function), delayInMs);
+      expect(chrome.alarms.create).toHaveBeenCalledWith(
+        `${userUuid}__${ScheduledTaskNames.loginStrategySessionTimeout}`,
+        { delayInMinutes: 0.5 },
+        expect.any(Function),
+      );
+    });
   });
 });

apps/browser/src/platform/services/browser-task-scheduler.service.ts

@@ -52,15 +52,22 @@ export class BrowserTaskSchedulerServiceImplementation
     taskName: ScheduledTaskName,
     delayInMs: number,
   ): Promise<number | NodeJS.Timeout> {
-    const delayInMinutes = delayInMs / 1000 / 60;
-    if (delayInMinutes < 1) {
-      return super.setTimeout(taskName, delayInMs);
-    }
-
     this.validateRegisteredTask(taskName);
 
+    const delayInMinutes = delayInMs / 1000 / 60;
     const alarmName = await this.getActiveUserAlarmName(taskName);
-    await this.scheduleAlarm(alarmName, { delayInMinutes });
+    await this.scheduleAlarm(alarmName, {
+      delayInMinutes: this.getUpperBoundDelayInMinutes(delayInMinutes),
+    });
+
+    // If the delay is less than a minute, we want to attempt to trigger the task through a setTimeout.
+    // The alarm previously scheduled will be used as a backup in case the setTimeout fails.
+    if (delayInMinutes < 1) {
+      return globalThis.setTimeout(async () => {
+        await this.triggerTask(alarmName);
+        await this.clearScheduledAlarm(alarmName);
+      }, delayInMs);
+    }
   }
 
   /**
@@ -396,4 +403,16 @@ export class BrowserTaskSchedulerServiceImplementation
   private isNonChromeEnvironment(): boolean {
     return typeof browser !== "undefined" && !!browser.alarms;
   }
+
+  /**
+   * Gets the upper bound delay in minutes for a given delay in minutes. This is
+   * used to ensure that the delay is at least 1 minute in non-Chrome environments.
+   * In Chrome environments, the delay can be as low as 0.5 minutes.
+   *
+   * @param delayInMinutes - The delay in minutes.
+   */
+  private getUpperBoundDelayInMinutes(delayInMinutes: number): number {
+    const minDelayInMinutes = this.isNonChromeEnvironment() ? 1 : 0.5;
+    return Math.max(minDelayInMinutes, delayInMinutes);
+  }
 }