function declaration vs function expression

function declaration vs function expression

function expression:
  foo() //try to call foo TypeError!
  var foo = function () {
    // do something
  };
  
is more like:
  var foo;
  
  foo() //try to call foo TypeError!
  foo = function() {
    // do something
  }

  the variable (name identifier is hoisted), but the assignment is not;

function declaration:
foo();

function foo() {
    // no problem!
}