JS scope/hoisting quiz

gistfile1.js

// Without cheating by running the code,
// what do these 3 result in?

function foo(a) {
   a();
   function a() {
      console.log("yay");
   }
}

foo(); // ??
foo( undefined ); // ??
foo( function(){ console.log("bam"); } ); // ??

yay
yay
yay