diff --git a/public/workerware/workerware.js b/public/workerware/workerware.js
index 7d80832..87591e6 100644
--- a/public/workerware/workerware.js
+++ b/public/workerware/workerware.js
@@ -41,7 +41,7 @@ const validEvents = [
 
 class WorkerWare {
   constructor(opt) {
-    this._opt = opt;
+    this._opt = Object.assign({}, defaultOpt, opt);
     this._middlewares = [];
   }
   info() {
@@ -144,4 +144,4 @@ class WorkerWare {
       error: undefined,
     };
   }
-}
+}
\ No newline at end of file