Hoisting, function declarations vs function expressions

gistfile1.js

console.log('--------- Hoisting:');

(function () {

    //console.log('3.1:', a); // -> ReferenceError
    
    console.log('3.2:', b); // -> undefined
    var b = 1;


    console.log('3.3:', c); // -> undefined
    if (false) {
        var c = 1;
    }
    console.log('3.4:', c); // -> undefined


    var d = 10;
    (function () {
        if (d === 10) {
            var d = 20;
        }
        console.log('3.5:', d); // -> undefined
    })();



})();

console.log('--------- FD vs FE:');


(function () {

    a('4.1:'); // -> 2
    var a = function (i) {
        console.log(i, '1');
    };
    function a(i) {
        console.log(i, '2');
    }
    a('4.2:'); // -> 1


    function b() {
        console.log('4.3: 1');
    }
    function b() {
        console.log('4.4: 2');
    }
    b(); // -> 2


    var c1 = function c2(i) {
        console.log(i, c1, c2);
    };
    c1('4.5:'); // -> function, function
    //c2('4.6:'); // -> ReferenceError

})();