Functions and their scope: declarations vs. expressions

functionsDefinitions.js

/* 
  Resources:
  - https://javascriptweblog.wordpress.com/2010/07/06/function-declarations-vs-function-expressions/
  - http://www.2ality.com/2011/04/ecmascript-5-spec-lexicalenvironment.html
*/

// function declarations uses the VariableEnvironment as scope
function f() {
  return 12;
}

// function expressions use the LexicalEnvironment
// annoymous
var f = function () {
  return 12;
};

// named
var f = function foo () {
  return 12;
};

// self invoking
(function f() {
  return 12;
})();

// Examples
function foo() {
  var bar = function () {
    return 3;
  };
  return bar();
  var bar = function () {
    return 8;
  };
}
console.log(foo()); // 8

function boo() {
  function bar() {
    return 3;
  }
  return bar();
  function bar() {
    return 8;
  }
}
console.log(boo()); // 3