diff --git a/package.json b/package.json
index 7b9f993a..619c8aaf 100644
--- a/package.json
+++ b/package.json
@@ -55,7 +55,7 @@
     "@commitlint/cli": "^13.1.0",
     "@commitlint/config-conventional": "^13.1.0",
     "@types/cpx": "^1.5.2",
-    "@types/jasmine": "^3.9.1",
+    "@types/jasmine": "~3.10.1",
     "@types/jasminewd2": "~2.0.10",
     "@types/node": "12.12.41",
     "@uploadx/core": "^4.4.2",
@@ -65,9 +65,9 @@
     "core-js": "2.6.11",
     "cpx": "^1.5.0",
     "husky": "^7.0.2",
-    "jasmine-core": "^3.9.0",
+    "jasmine-core": "~3.10.1",
     "jasmine-spec-reporter": "^7.0.0",
-    "karma": "^5.2.3",
+    "karma": "~6.3.5",
     "karma-chrome-launcher": "~3.1.0",
     "karma-coverage-istanbul-reporter": "~3.0.3",
     "karma-jasmine": "~4.0.1",
diff --git a/src/uploadx/lib/tus.spec.ts b/src/uploadx/lib/tus.spec.ts
index a62df1c6..3c029ac5 100644
--- a/src/uploadx/lib/tus.spec.ts
+++ b/src/uploadx/lib/tus.spec.ts
@@ -4,35 +4,38 @@ import { Tus } from './tus';
 // tslint:disable: no-any
 const fileWithType = new File(['123456'], 'filename.txt', { type: 'text/plain' });
 describe('getFileUrl', () => {
-  let upx: Tus;
+  let uploader: Tus;
   let req: jasmine.Spy;
   let getValueFromResponse: jasmine.Spy;
   it('should set headers', async () => {
-    upx = new Tus(fileWithType, {}, () => {}, {} as Ajax);
-    req = spyOn<any>(upx, 'request').and.callFake(({ headers }: any) => {
+    uploader = new Tus(fileWithType, {}, () => {}, {} as Ajax);
+    req = spyOn<any>(uploader, 'request').and.callFake(({ headers }: any) => {
       expect(headers['Upload-Metadata']).toContain('name');
       expect(headers['Upload-Length']).toEqual('6');
     });
-    getValueFromResponse = spyOn<any>(upx, 'getValueFromResponse').and.returnValue('/12345678');
-    expect(upx.name).toEqual('filename.txt');
-    expect(upx.size).toEqual(6);
-    expect(await upx.getFileUrl()).toEqual('/12345678');
+    getValueFromResponse = spyOn<any>(uploader, 'getValueFromResponse').and.returnValue(
+      '/12345678'
+    );
+    expect(uploader.name).toEqual('filename.txt');
+    expect(uploader.size).toEqual(6);
+    expect(await uploader.getFileUrl()).toEqual('/12345678');
     expect(req).toHaveBeenCalled();
     expect(getValueFromResponse).toHaveBeenCalled();
   });
 });
 describe('sendFileContent', () => {
-  let upx: Tus;
+  let uploader: Tus;
   let req: jasmine.Spy;
   let getOffsetFromResponse: jasmine.Spy;
   it('should set Upload-Offset header', async () => {
-    upx = new Tus(fileWithType, {}, () => {}, {} as Ajax);
-    req = spyOn<any>(upx, 'request').and.callFake(({ headers }: any) => {
+    uploader = new Tus(fileWithType, {}, () => {}, {} as Ajax);
+    uploader.offset = 0;
+    req = spyOn<any>(uploader, 'request').and.callFake(({ headers }: any) => {
       expect(headers['Content-Type']).toEqual('application/offset+octet-stream');
       expect(headers['Upload-Offset']).toEqual('0');
     });
-    getOffsetFromResponse = spyOn<any>(upx, 'getOffsetFromResponse').and.returnValue(6);
-    expect(await upx.sendFileContent()).toEqual(6);
+    getOffsetFromResponse = spyOn<any>(uploader, 'getOffsetFromResponse').and.returnValue(6);
+    expect(await uploader.sendFileContent()).toEqual(6);
     expect(req).toHaveBeenCalled();
     expect(getOffsetFromResponse).toHaveBeenCalled();
   });
diff --git a/src/uploadx/lib/uploader.spec.ts b/src/uploadx/lib/uploader.spec.ts
index 4a7ad3c9..5f9e9507 100644
--- a/src/uploadx/lib/uploader.spec.ts
+++ b/src/uploadx/lib/uploader.spec.ts
@@ -133,11 +133,13 @@ describe('Uploader', () => {
       const updateToken = spyOn<any>(uploader, 'updateToken').and.callThrough();
       const getFileUrl = spyOn(uploader, 'getFileUrl').and.callThrough();
       const getOffset = spyOn(uploader, 'getOffset').and.callThrough();
+      const sendFileContent = spyOn(uploader, 'sendFileContent').and.callThrough();
       const cleanup = spyOn<any>(uploader, 'cleanup').and.callThrough();
       await uploader.upload();
       expect(updateToken).toHaveBeenCalledTimes(1);
       expect(getFileUrl).toHaveBeenCalledTimes(1);
-      expect(getOffset).toHaveBeenCalledTimes(0);
+      expect(getOffset).toHaveBeenCalledTimes(1);
+      expect(sendFileContent).toHaveBeenCalledTimes(1);
       expect(cleanup).toHaveBeenCalled();
       expect(uploader.status).toEqual('complete');
     });
diff --git a/src/uploadx/lib/uploader.ts b/src/uploadx/lib/uploader.ts
index e5476083..590dd750 100644
--- a/src/uploadx/lib/uploader.ts
+++ b/src/uploadx/lib/uploader.ts
@@ -48,7 +48,7 @@ export abstract class Uploader implements UploadState {
   /** Auth token/tokenGetter */
   token: UploadxControlEvent['token'];
   /** Byte offset within the whole file */
-  offset? = 0;
+  offset?: number;
   /** Retries handler */
   retry: RetryHandler;
   canceler = new Canceler();
diff --git a/src/uploadx/lib/uploaderx.spec.ts b/src/uploadx/lib/uploaderx.spec.ts
index 4d2d1fa3..7bcab975 100644
--- a/src/uploadx/lib/uploaderx.spec.ts
+++ b/src/uploadx/lib/uploaderx.spec.ts
@@ -6,52 +6,57 @@ const fileWithType = new File(['123456'], 'filename.txt', { type: 'text/plain' }
 const fileWithoutType = new File([''], 'filename');
 
 describe('getFileUrl', () => {
-  let upx: UploaderX;
+  let uploader: UploaderX;
   let req: jasmine.Spy;
   let getValueFromResponse: jasmine.Spy;
   it('should set headers', async () => {
-    upx = new UploaderX(fileWithType, {}, () => {}, {} as Ajax);
-    req = spyOn<any>(upx, 'request').and.callFake(({ headers }: any) => {
+    uploader = new UploaderX(fileWithType, {}, () => {}, {} as Ajax);
+    req = spyOn<any>(uploader, 'request').and.callFake(({ headers }: any) => {
       expect(headers['X-Upload-Content-Type']).toEqual('text/plain');
       expect(headers['X-Upload-Content-Length']).toEqual('6');
     });
-    getValueFromResponse = spyOn<any>(upx, 'getValueFromResponse').and.returnValue('/12345678');
-    expect(upx.name).toEqual('filename.txt');
-    expect(upx.size).toEqual(6);
-    expect(await upx.getFileUrl()).toEqual('/12345678');
+    getValueFromResponse = spyOn<any>(uploader, 'getValueFromResponse').and.returnValue(
+      '/12345678'
+    );
+    expect(uploader.name).toEqual('filename.txt');
+    expect(uploader.size).toEqual(6);
+    expect(await uploader.getFileUrl()).toEqual('/12345678');
     expect(req).toHaveBeenCalled();
     expect(getValueFromResponse).toHaveBeenCalled();
   });
   it('should set default type header', async () => {
-    upx = new UploaderX(fileWithoutType, {}, () => {}, {} as Ajax);
-    req = spyOn<any>(upx, 'request').and.callFake(({ headers }: any) => {
+    uploader = new UploaderX(fileWithoutType, {}, () => {}, {} as Ajax);
+    req = spyOn<any>(uploader, 'request').and.callFake(({ headers }: any) => {
       expect(headers['X-Upload-Content-Type']).toEqual('application/octet-stream');
       expect(headers['X-Upload-Content-Length']).toEqual('0');
     });
-    getValueFromResponse = spyOn<any>(upx, 'getValueFromResponse').and.returnValue('/12345678');
-    expect(upx.name).toEqual('filename');
-    expect(upx.size).toEqual(0);
-    await upx.getFileUrl();
+    getValueFromResponse = spyOn<any>(uploader, 'getValueFromResponse').and.returnValue(
+      '/12345678'
+    );
+    expect(uploader.name).toEqual('filename');
+    expect(uploader.size).toEqual(0);
+    await uploader.getFileUrl();
     expect(req).toHaveBeenCalled();
     expect(getValueFromResponse).toHaveBeenCalled();
   });
 });
 
 describe('sendFileContent', () => {
-  let upx: UploaderX;
+  let uploaderX: UploaderX;
   let req: jasmine.Spy;
   let getValueFromResponse: jasmine.Spy;
   it('should set Content-Range header', async () => {
-    upx = new UploaderX(fileWithType, {}, () => {}, {} as Ajax);
-    req = spyOn<any>(upx, 'request').and.callFake(({ headers }: any) => {
+    uploaderX = new UploaderX(fileWithType, {}, () => {}, {} as Ajax);
+    uploaderX.offset = 0;
+    req = spyOn<any>(uploaderX, 'request').and.callFake(({ headers }: any) => {
       expect(headers['Content-Type']).toEqual('application/octet-stream');
       expect(headers['Content-Range']).toEqual('bytes 0-5/6');
     });
-    getValueFromResponse = spyOn<any>(upx, 'getValueFromResponse').and.returnValue(
+    getValueFromResponse = spyOn<any>(uploaderX, 'getValueFromResponse').and.returnValue(
       'Range: bytes=0-5'
     );
-    upx.responseStatus = 308;
-    expect(await upx.sendFileContent()).toEqual(6);
+    uploaderX.responseStatus = 308;
+    expect(await uploaderX.sendFileContent()).toEqual(6);
     expect(req).toHaveBeenCalled();
     expect(getValueFromResponse).toHaveBeenCalled();
   });