function variebles() {
    const constant = 0;
    console.log(constant);
    let varieble = 5;
    console.log(varieble);
    varieble = 8;
    console.log(varieble)
    constant = 5;
}

function dataTypes() {
    let someVarieble;
    console.log(typeof someVarieble); // undefined
    someVarieble = 5; 
    console.log(typeof someVarieble); // number
    someVarieble = '5'; 
    console.log(typeof someVarieble); // string 
    someVarieble = true;
    console.log(typeof someVarieble); // boolean
    someVarieble = null;
    console.log(typeof someVarieble); // null   
}

function castOfTypes() {
    let someNumber = 5;
    let someString = '5';
    console.log(someNumber - someString);
    console.log(someNumber * someString);
    console.log(someNumber / someString);
    console.log(someNumber + someString);
    console.log(!someNumber);
}

function whatIsNaN() {
    let someString = 'haHaaaa';
    console.log(someString * 50); // NaN
    let someNaN = someString -1;
    console.log(someNaN == someNaN) // false
}

function falsyValues() {
    console.log('' == true);
    console.log(0 == true);
    console.log(false == true);
    console.log(null == true);
    console.log(undefined == true);
    console.log(NaN == true);
}

function stringsImmutable() {
    let someString = 'Dock';
    console.log(someString[1]);
    someString[1] = 'i';
    console.log(someString);
}

function jsArrays() {
    const someArray = [];
    console.log(someArray.length);
    someArray[10] = 'lol';
    console.log(someArray.length);
    changeArray(someArray);
    console.log(someArray);
}

function changeArray(array) {
    const lol = array;
    lol[0] = 'haHaaa';
}