[FSSDK-11879] flush events without closing client on page unload

Author: raju-opti

lib/client_factory.ts

@@ -31,7 +31,7 @@ export type OptimizelyFactoryConfig = Config & {
   requestHandler: RequestHandler;
 }
 
-export const getOptimizelyInstance = (config: OptimizelyFactoryConfig): Client => {
+export const getOptimizelyInstance = (config: OptimizelyFactoryConfig): Optimizely => {
   const { 
     clientEngine,
     clientVersion,

lib/event_processor/batch_event_processor.ts

@@ -230,14 +230,14 @@ export class BatchEventProcessor extends BaseService implements EventProcessor {
     });
   }
 
-  private async flush(closing = false): Promise<void> {
+  private async flush(useClosingDispatcher = false): Promise<void> {
     const batch = this.createNewBatch();
     if (!batch) {
       return;
     }
 
     this.dispatchRepeater.reset();
-    this.dispatchBatch(batch, closing);
+    this.dispatchBatch(batch, useClosingDispatcher);
   }
 
   async process(event: ProcessableEvent): Promise<void> {
@@ -332,6 +332,10 @@ export class BatchEventProcessor extends BaseService implements EventProcessor {
     }
   }
 
+  flushImmediately(): Promise<unknown> {
+    return this.flush(true);
+  }
+  
   stop(): void {
     if (this.isDone()) {
       return;

lib/event_processor/event_processor.ts

@@ -28,4 +28,5 @@ export interface EventProcessor extends Service {
   process(event: ProcessableEvent): Promise<unknown>;
   onDispatch(handler: Consumer<LogEvent>): Fn;
   setLogger(logger: LoggerFacade): void;
+  flushImmediately(): Promise<unknown>;
 }

lib/event_processor/forwarding_event_processor.ts

@@ -69,4 +69,8 @@ export class ForwardingEventProcessor extends BaseService implements EventProces
   onDispatch(handler: Consumer<LogEvent>): Fn {
     return this.eventEmitter.on('dispatch', handler);
   }
+
+  flushImmediately(): Promise<unknown> {
+    return Promise.resolve();
+  }
 }

lib/index.browser.ts

@@ -37,7 +37,7 @@ export const createInstance = function(config: Config): Client {
     window.addEventListener(
       unloadEvent,
       () => {
-        client.close();
+        client.flushImmediately();
       },
     );
   }

lib/odp/event_manager/odp_event_manager.ts

@@ -42,6 +42,7 @@ export interface OdpEventManager extends Service {
   updateConfig(odpIntegrationConfig: OdpIntegrationConfig): void;
   sendEvent(event: OdpEvent): void;
   setLogger(logger: LoggerFacade): void;
+  flushImmediately(): Promise<unknown>;
 }
 
 export type RetryConfig = {
@@ -160,6 +161,10 @@ export class DefaultOdpEventManager extends BaseService implements OdpEventManag
     this.startPromise.resolve();
   }
 
+  flushImmediately(): Promise<unknown> {
+    return this.flush();
+  }
+
   stop(): void {
     if (this.isDone()) {
       return;

lib/odp/odp_manager.spec.ts

@@ -53,6 +53,7 @@ const getMockOdpEventManager = () => {
     sendEvent: vi.fn(),
     makeDisposable: vi.fn(),
     setLogger: vi.fn(),
+    flushImmediately: vi.fn(),
   };
 };
 

lib/odp/odp_manager.ts

@@ -40,6 +40,7 @@ export interface OdpManager extends Service {
   setClientInfo(clientEngine: string, clientVersion: string): void;
   setVuid(vuid: string): void;
   setLogger(logger: LoggerFacade): void;
+  flushImmediately(): Promise<unknown>;
 }
 
 export type OdpManagerConfig = {
@@ -145,6 +146,10 @@ export class DefaultOdpManager extends BaseService implements OdpManager {
     this.stopPromise.reject(error);
   }
 
+  flushImmediately(): Promise<unknown> {
+    return this.eventManager.flushImmediately();
+  }
+
   stop(): void {
     if (this.isDone()) {
       return;

lib/optimizely/index.ts

@@ -1243,6 +1243,24 @@ export default class Optimizely extends BaseService implements Client {
     }
   }
 
+  flushImmediately(): Promise<unknown> {
+    const ret = [];
+    
+    if (!this.isRunning()) {
+      return Promise.resolve();
+    }
+
+    if (this.eventProcessor) {
+      ret.push(this.eventProcessor.flushImmediately());
+    }
+
+    if(this.odpManager) {
+      ret.push(this.odpManager.flushImmediately());
+    }
+
+    return Promise.all(ret);
+  }
+
   /**
    * Stop background processes belonging to this instance, including:
    *