ThrowTypeError is a singleton object On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE". PASS functionCaller1 === functionCaller2 is true PASS functionCaller1 === functionArguments1 is true PASS argumentsCaller1 is undefined PASS functionCaller1 === argumentsCallee1 is true PASS boundCaller1 is undefined PASS boundArguments1 is undefined PASS functionCaller2 === functionArguments2 is true PASS argumentsCaller2 is undefined PASS functionCaller2 === argumentsCallee2 is true PASS boundCaller2 is undefined PASS boundArguments2 is undefined PASS successfullyParsed is true TEST COMPLETE