fix: switch to polling (#766)

Author: kwasniew

src/repository/adaptive-fetcher.ts

@@ -52,25 +52,23 @@ export class AdaptiveFetcher extends EventEmitter implements FetcherInterface {
       return;
     }
 
-    this.emit(UnleashEvents.Mode, { from: 'streaming', to: 'polling' });
-
     this.currentFetcher.stop();
     this.currentFetcher = this.pollingFetcher;
 
     await this.currentFetcher.start();
+    this.emit(UnleashEvents.Mode, { from: 'streaming', to: 'polling' });
   }
 
   private async switchToStreaming() {
     if (this.currentFetcher === this.streamingFetcher) {
       return;
     }
 
-    this.emit(UnleashEvents.Mode, { from: 'polling', to: 'streaming' });
-
     this.currentFetcher.stop();
     this.currentFetcher = this.streamingFetcher;
 
     await this.currentFetcher.start();
+    this.emit(UnleashEvents.Mode, { from: 'polling', to: 'streaming' });
   }
 
   async start(): Promise<void> {

src/repository/polling-fetcher.ts

@@ -32,6 +32,7 @@ export class PollingFetcher extends EventEmitter implements FetcherInterface {
   }
 
   async start(): Promise<void> {
+    this.stopped = false;
     await this.fetch();
   }
 

src/repository/streaming-fetcher.ts

@@ -9,8 +9,6 @@ import { FetcherInterface, StreamingFetchingOptions } from './fetcher';
 export class StreamingFetcher extends EventEmitter implements FetcherInterface {
   private eventSource: EventSource | undefined;
 
-  private stopped = false;
-
   private options: StreamingFetchingOptions;
 
   constructor(options: StreamingFetchingOptions) {
@@ -85,7 +83,6 @@ export class StreamingFetcher extends EventEmitter implements FetcherInterface {
   }
 
   stop() {
-    this.stopped = true;
     if (this.eventSource) {
       this.eventSource.close();
       this.eventSource = undefined;

src/test/repository.test.ts

@@ -1938,8 +1938,6 @@ test('setMode can switch from streaming to polling mode', async (t) => {
   t.is(repo.getMode(), 'polling');
   t.true(eventSource.closed);
 
-  await repo.fetch();
-
   toggles = repo.getToggles();
   t.is(toggles[0].enabled, true);