diff --git a/lib/internal/cluster/primary.js b/lib/internal/cluster/primary.js
index 991cfff6e6df61..e8113411790a11 100644
--- a/lib/internal/cluster/primary.js
+++ b/lib/internal/cluster/primary.js
@@ -252,19 +252,21 @@ cluster.disconnect = function(cb) {
     intercom.once('disconnect', cb);
 };
 
+const methodMessageMapping = {
+  close,
+  exitedAfterDisconnect,
+  listening,
+  online,
+  queryServer,
+};
+
 function onmessage(message, handle) {
   const worker = this;
 
-  if (message.act === 'online')
-    online(worker);
-  else if (message.act === 'queryServer')
-    queryServer(worker, message);
-  else if (message.act === 'listening')
-    listening(worker, message);
-  else if (message.act === 'exitedAfterDisconnect')
-    exitedAfterDisconnect(worker, message);
-  else if (message.act === 'close')
-    close(worker, message);
+  const fn = methodMessageMapping[message.act];
+
+  if (typeof fn === 'function')
+    fn(worker, message);
 }
 
 function online(worker) {