A simple wrapper function in JavaScript - more fun with closures

gistfile1.js

var truth = function() { return true; };
var relativeTruth = function() { return false; };

var assert = function(func) {
  return func() == true;
};

var wrapper = function(func) {
  
  // perform setup work here
  // executed once when wrapper() is executed
  console.info('the wrap is set');
  
  // The result of calling wrapper() is to return an anonymous
  // function that has wrapped the original function in a closure
  return function() {
    // perform wrapped work here
    // executed every time the wrapped function is called
    console.info('wrap, wrap, wrap, the boys are marching');
    
    // now call the original method
    var args = Array.prototype.slice.call(arguments)[0];
    return func(args);
  }
};

assert = wrapper(assert); // the wrap is set

console.info(assert(truth)); // 'wrap wrap wrap the boys are marching', true
console.info(assert(relativeTruth)) // 'wrap wrap wrap the boys are marching', false

I'm confused with "arguments" varriable. Can you please explain a bit more detail. Thanks :)

maybe too late, i am a beginner of javascript;)
line 22 arguments means the args of the function which wrapper returns, just like line 27 assert = wrapper(assert)
the left hand assert;
forgive my poor english:)

Shouldn't you call func like this?

return func.apply(this, args);

Currently it just calls func by passing arguments in a single Array.

See: https://gist.github.com/kimmobrunfeldt/ca53975d4ae9a7851fa9

Let's say I do:

var spy = function(func) {
  return function() {
        var args = [].splice.call(arguments, 0);
        console.log('function (', args, ')');
    return func(args);
  }
};

and then I do:
alert=spy(alert);
alert("hello");

this works, but how can I get the function name inside the closure?
so that it will do console.log(funcname,args)
??

oh and by the way this is a better wrapper:

var spy = function(func) {
  return function() {
        var args = [].splice.call(arguments, 0);
        console.log('function (', args, ')');
    return func.apply(this, args);
  }
};