JavaScript Array Properties

length
	Sets or returns the number of elements in an array.

prototype 
	Allows you to add new properties and methods to an Array object.


//length
/*
const countries = ["USA", "UK", "Canada", "Myanmar", "Singapore"];

function showLength(){
    document.getElementById("demo").innerHTML = countries.length;
}

//prototype

Array.prototype.tnwCase = function(){
    for(let i = 0; i < this.length; i++){
        this[i] = this[i].toLowerCase(); //lower case
    }
};

const countries = ["USA", "UK", "Canada", "Myanmar", "Singapore"];
countries.tnwCase();

function tnwFun(){
    document.getElementById("demo").innerHTML = countries;
}*/

//Another example of prototype property

function Person(first, middle, last){
    this.firstName = first;
    this.middleName = middle;
    this.lastName = last;
}

const myFriend = new Person("Aung", "Kyaw", "Soe");
Person.prototype.nationality = "Myanmar";
Person.prototype.age = 35;

function tnwFun(){
    document.getElementById("demo").innerHTML = myFriend.age;
}

To see video in YouTube.