diff --git a/src/node_zlib.cc b/src/node_zlib.cc
index 1dabd3e63d9340..12c418fd28438f 100644
--- a/src/node_zlib.cc
+++ b/src/node_zlib.cc
@@ -314,7 +314,7 @@ class ZCtx : public AsyncWrap {
         }
         break;
       default:
-        CHECK(0 && "wtf?");
+        UNREACHABLE();
     }
 
     // pass any errors back to the main thread to deal with.
@@ -525,7 +525,7 @@ class ZCtx : public AsyncWrap {
             ->AdjustAmountOfExternalAllocatedMemory(kInflateContextSize);
         break;
       default:
-        CHECK(0 && "wtf?");
+        UNREACHABLE();
     }
 
     ctx->dictionary_ = reinterpret_cast<Bytef *>(dictionary);