Sample closure function with sum example

BTCbank.js

var BTCbank = function(BTC_balanace) {

    return grandpa = (moneyspent) => {
        // grandpa

        BTC_balanace -= moneyspent;

        return dad = (moneyspent) => {
            // dad
            BTC_balanace -= moneyspent;

            return me = (moneyspent) => {
                // me
                return BTC_balanace -= moneyspent;
            }

        }

    }

};

// step-1
// deposit 1000 to BTCbank

var bankBalance = BTCbank(1000);


// step-2
// now grandpa spending amount is 300

var afterGrandpaSpending = bankBalance(300);

// step-3
// now grandpa spending amount is 200

var afterDadSpending = afterGrandpaSpending(200);

// step-4
// now grandpa spending amount is 499

var aftermyDonaion = afterDadSpending(499);

console.log(aftermyDonaion);


/// simple way 
/// console.dir(BTCbank(1000)(400)(100)(499));