JavaScript Hoisting

gistfile1.js

//1. variable declaration:

// declaration
function foo() { 
  return true;
  var x = 1; 
}

// interpretation 
funciton foo() {
  var x;
  return true;
  x = 1;
}

//2. function declaration:

// declaration
function foo() {
  foo1(); // all good
  foo2(); // TypeError "foo2 is not a function"
  foo3(); // TypeError "foo3 is not a function"

  function foo1() {}; // function declaration
  var foo2 = function () {}; // function expression 
  var foo3 = function foo4() {}; // named function expression
}

// interpretation
function foo() {
  function foo1() {}
  var foo2;
  var foo3;
  
  foo1();
  foo2();

  foo2 = function () {};
  foo3 = function foo4() {};
}