diff --git a/src/helper.ts b/src/helper.ts
index 029f134..3b82b73 100644
--- a/src/helper.ts
+++ b/src/helper.ts
@@ -1,12 +1,11 @@
 import unpack, { IWasmModule } from './unpack';
-import unpackWasm from './unpack.wasm';
 
 const initializeWasm = async (wasmPath: string | undefined): Promise<IWasmModule> => {
   try {
     const wasmModule: IWasmModule = await unpack({
       locateFile(path: string) {
         if (path.endsWith('.wasm')) {
-          return wasmPath ? wasmPath : unpackWasm;
+          return wasmPath ? wasmPath : 'unpack.wasm';
         }
         return path;
       }
@@ -17,4 +16,5 @@ const initializeWasm = async (wasmPath: string | undefined): Promise<IWasmModule
     throw new Error(`Error initializing the WASM module: ${err}`);
   }
 };
+
 export default initializeWasm;
diff --git a/src/index.ts b/src/index.ts
index b2b2c38..af64549 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -16,7 +16,7 @@ export interface IUnpackJSAPI {
   extract: (url: string) => Promise<IFileData[]>;
 }
 
-export const initUntarJS = async (wasmPath: string | undefined): Promise<IUnpackJSAPI> => {
+export const initUntarJS = async (wasmPath?: string): Promise<IUnpackJSAPI> => {
   let wasmModule: IWasmModule | undefined = undefined;
   try {
     wasmModule = await initializeWasm(wasmPath);
diff --git a/tests/index.spec.ts b/tests/index.spec.ts
index a1259b2..7b0b272 100644
--- a/tests/index.spec.ts
+++ b/tests/index.spec.ts
@@ -1,4 +1,4 @@
-import untarjs from '../src/index';
+import { initUntarJS } from '../src/index';
 
 jest.mock('../src/helper', () => ({
   __esModule: true,
@@ -14,6 +14,8 @@ jest.mock('../src/index', () => {
 
 describe('extract', () => {
   it('should download and extract data successfully', async () => {
+    const untarjs = await initUntarJS();
+
     const mockData = new Uint8Array([1, 2, 3, 4]);
     const extractedData = {
       data: new Uint8Array([5, 6, 7, 8]),