how to fix this error TypeError [ERR_INVALID_CALLBACK]: Callback must be a function

Question

I am a beginner to the nodejs. When I type the below, the code error occurs like this:

TypeError [ERR_INVALID_CALLBACK]: Callback must be a function

Answer 1

This error hit me in the face when I was doing the following;

var hello = myfunction( callme() );

rather than

var hello = myfunction( callme );