diff --git a/package.json b/package.json
index 5586a64d..c984dc6a 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "ngx-uploader",
-  "version": "3.1.1",
+  "version": "3.1.2",
   "main": "bundles/ngx-uploader.umd.js",
   "module": "index.js",
   "esnext": "index.js",
diff --git a/src/ngx-uploader/classes/ngx-uploader.class.ts b/src/ngx-uploader/classes/ngx-uploader.class.ts
index fd016653..2257e39d 100644
--- a/src/ngx-uploader/classes/ngx-uploader.class.ts
+++ b/src/ngx-uploader/classes/ngx-uploader.class.ts
@@ -120,7 +120,7 @@ export class NgUploaderService {
           });
         break;
         case 'uploadAll':
-          let concurrency = event.concurrency > 0 ? event.concurrency : Number.POSITIVE_INFINITY;
+          const concurrency = event.concurrency > 0 ? event.concurrency : Number.POSITIVE_INFINITY;
 
           const subscriber = Subscriber.create((data: UploadOutput) => {
             this.serviceEvents.emit(data);