Moved write flag constants to base module
diff --git a/src/node/index.js b/src/node/index.js
index 93c65ac..889b0ac 100644
--- a/src/node/index.js
+++ b/src/node/index.js
@@ -145,6 +145,11 @@
 exports.callError = grpc.callError;
 
 /**
+ * Write flag name to code number mapping
+ */
+exports.writeFlags = grpc.writeFlags;
+
+/**
  * Credentials factories
  */
 exports.Credentials = grpc.Credentials;