Fix array length check condition (#6154)

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[cvat-core](https://github.com/opencv/cvat/tree/develop/cvat-core#versioning),

[cvat-data](https://github.com/opencv/cvat/tree/develop/cvat-data#versioning)
and

[cvat-ui](https://github.com/opencv/cvat/tree/develop/cvat-ui#versioning))

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CHANGELOG.md

@@ -36,6 +36,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   (<https://github.com/opencv/cvat/pull/6129>).
 - HRNet CPU serverless function
   (<https://github.com/opencv/cvat/pull/6150>)
+- Sending empty list of events
+  (<https://github.com/opencv/cvat/pull/6154>)
 
 ### Security
 - TDB

cvat-core/package.json

@@ -1,6 +1,6 @@
 {
   "name": "cvat-core",
-  "version": "9.1.0",
+  "version": "9.1.1",
   "description": "Part of Computer Vision Tool which presents an interface for client-side integration",
   "main": "src/api.ts",
   "scripts": {

cvat-core/src/logger-storage.ts

@@ -160,7 +160,7 @@ Object.defineProperties(LoggerStorage.prototype.save, {
         writable: false,
         enumerable: false,
         value: async function implementation() {
-            if (!this.collection) {
+            if (!this.collection.length) {
                 return;
             }