diff --git a/bin/callback.js b/bin/callback.js
index f9acc27..1bc0444 100644
--- a/bin/callback.js
+++ b/bin/callback.js
@@ -4,15 +4,7 @@ const CALLBACK_URL = process.env.CALLBACK_URL ? new URL(process.env.CALLBACK_URL
 const CALLBACK_TIMEOUT = process.env.CALLBACK_TIMEOUT || 5000
 const CALLBACK_OBJECTS = process.env.CALLBACK_OBJECTS ? JSON.parse(process.env.CALLBACK_OBJECTS) : {}
 
-/**
- * @return {Boolean}
- */
-exports.isCallbackSet = () => {
-  if (CALLBACK_URL) {
-    return true
-  }
-  return false
-}
+exports.isCallbackSet = !!CALLBACK_URL
 
 /**
  * @param {Uint8Array} update
diff --git a/bin/utils.js b/bin/utils.js
index 5e2cb08..1138961 100644
--- a/bin/utils.js
+++ b/bin/utils.js
@@ -118,7 +118,7 @@ class WSSharedDoc extends Y.Doc {
     }
     this.awareness.on('update', awarenessChangeHandler)
     this.on('update', updateHandler)
-    if (isCallbackSet()) {
+    if (isCallbackSet) {
       this.on('update', debounce(
         callbackHandler,
         CALLBACK_DEBOUNCE_WAIT,