NodeJS TypeError Callback is not a function
<p>I have the following piece of code:</p>

<pre><code>function fun1(callback){
  var result =  "result of function 1";
  callback(result)
};
function fun2(callback){
  var result =  "result of function 2";
  callback(result)
};

fun1(log); // displays "result of function 1"
fun2(log); // displays "result of function 2"
fun2(fun1(log)); // Type Error ...
</code></pre>

<p>Where log is simple function (i.e. console.log(data)...)
I'm wondering why fun2(fun1(log)) does not display "result of function 1" as one would expect. What is missing? Many thanks - Christian</p>