This is a simple demonstration about learned things on this tutorial. It doesn't cover all the functionalities shown in the tutorial, but there are few.

 

let num1 = 2;
let num2 = 10;
let operator = "s";

if (operator == "+") {
    console.log(num1 + num2);
} else if (operator == "-") {
    console.log(num1 - num2);
} else if(operator == "*") {
    console.log(num1 * num2);
} else if(operator == "/") {
    console.log(num1 / num2);
} else {
    console.log("Unsupported operator. Please choose from +, -, *, /.");
}

if (4 % 2 == 0 && 5 < 3) {
    console.log("Oh no...");
}

if (4 % 2 == 0 || 5 < 3) {
    console.log("Oh! This is convenient!");
}

let number = 3;

while (number <= 9) {
    console.log(number);
    number = number + 3;
}