We can write a function but not use it as a constructor until we add the keyword new in front of it

The keyword new determines whether or not a function is a constructor

it creates a new object, which is bound to this

the function is invoked with the value of this equal to the new object

it sets the new objects prototype to the prototype property of the constructor

it returns the object

function Users(fName, lName) {
this.firstname = fName;
this.lastName = lName;
};

var user1 = new Users("Luka","Tatarishvili");
Users.prototype.fullName = function() {
	return this.fristName + " " + this.lastName;
};

var user2 = new Users("Luka","Tatarishvili");

 it's prototype still has the full name method as a part of it even though we added it after creating object and of course the fullName works ass well on user2 that created after setting prototype

let newObj = {
    total:  65,
    increment: 1
}

const incrementTotal = function(obj, val){
    obj.increment = val;
    return function(){
        console.log(obj.total);
        obj.total = obj.total + obj.increment;
        console.log(obj.total);

    };
};
const incBy1 = incrementTotal(newObj, 1);
const incBy2 = incrementTotal(newObj, 2);
//  will be incremented by 10 
const incBy10 = incrementTotal(newObj, 10);

let theObj = {
    total:  65,
    increment: 1
}
// clone object
const cloneObj = function(obj){
    return JSON.parse(JSON.stringify(obj));
  
};


const incrementTotal = function(obj, val){
    let newObj = cloneObj(obj);
    newObj.increment = val;
    return function(){
        console.log(newObj.total+" Before increment");
        newObj.total = newObj.total + newObj.increment;
        console.log(newObj.total+" After increment");

    };
};

const incBy2 = incrementTotal(theObj, 2); // it will increment by 2
const incBy10 = incrementTotal(theObj, 10); // it will increment by 10
const incBy25 = incrementTotal(theObj, 25); // it will increment by 25
const incBy125 = incrementTotal(theObj, 25); // it will increment by 125
//and so on

APP_KEY

.env file

php artisan key:generate

function deepClone(obj) {
    let copy = {};

    if (null == obj || "object" != typeof obj) return obj;

    copy  = Object.create(obj.constructor.prototype)
    for (let key in obj){
        copy[key] = clone(obj[key])
    }
    return copy
}

function clone(obj) {
    let clone = {};

    for(let i in obj){
        if(obj[i] != null && typeof(obj[i]) == "object")
            clone[i] = clone(obj[i])
        else
            clone[i] = obj[i];
    }

    return clone;
}