Node.js tutorial server fails if the zip function invoked

thrift/tutorial/nodejs$ make tutorialserver
NODE_PATH="../../lib/nodejs:../../lib/nodejs/lib:" /usr/bin/nodejs NodeServer.js

thrift/tutorial/rb$ make tutorialclient
/home/sekikn/repos/thrift/compiler/cpp/thrift --gen rb -r ../../tutorial/tutorial.thrift
/home/sekikn/.rbenv/shims/ruby RubyClient.rb
Unable to load thrift_native extension. Defaulting to pure Ruby libraries.
ping()
/home/sekikn/repos/thrift/lib/rb/lib/thrift/protocol/base_protocol.rb:256: warning: constant ::Fixnum is deprecated
/home/sekikn/repos/thrift/lib/rb/lib/thrift/protocol/base_protocol.rb:296: warning: constant ::Fixnum is deprecated
1+1=2
1+4=5
15-10=5
Log: 5
InvalidOperation: Cannot divide by 0
zip

ping()
add( 1 , 1 )
add( 1 , 4 )
calculate( 1 , { num1: 15, num2: 10, op: 2, comment: null } )
getStruct( 1 )
calculate( 1 , { num1: 1, num2: 0, op: 4, comment: null } )
zip()
events.js:183
      throw er; // Unhandled 'error' event
      ^

ReferenceError: result is not defined
    at Object.zip (/home/sekikn/repos/thrift/tutorial/nodejs/NodeServer.js:80:5)
    at exports.Processor.CalculatorProcessor.process_zip (/home/sekikn/repos/thrift/tutorial/nodejs/gen-nodejs/Calculator.js:731:17)
    at exports.Processor.CalculatorProcessor.process (/home/sekikn/repos/thrift/tutorial/nodejs/gen-nodejs/Calculator.js:599:39)
    at /home/sekikn/repos/thrift/lib/nodejs/lib/thrift/server.js:67:21
    at Socket.<anonymous> (/home/sekikn/repos/thrift/lib/nodejs/lib/thrift/buffered_transport.js:59:5)
    at emitOne (events.js:116:13)
    at Socket.emit (events.js:211:7)
    at addChunk (_stream_readable.js:263:12)
    at readableAddChunk (_stream_readable.js:250:11)
    at Socket.Readable.push (_stream_readable.js:208:10)
Makefile:639: recipe for target 'tutorialserver' failed
make: *** [tutorialserver] Error 1

 78   zip: function() {
 79     console.log("zip()");
 80     result(null);
 81   }