CODEWITHSUNDEEP
javascriptcalculator
ponpokopino
ponpokopino

Reputation: 33

Javascript interest calculator, how to return values with two different rates

I have this earning calculator function

EarningsCalculator.prototype.computeEarning = function (rate, investedValue) {

    var earnings = {};
    var currentState = investedValue;
    for (var i = 0; i <= 5; i++) {

            earning=currentState*rate;

            currentState = currentState + earning;

        earnings[i] = currentState;
    }

    return earnings;
}

It takes an "invested value" and based on a give rate, it calculates earning, which in this case is limited to 5 years with a for loop. What I need is to calculate earnings[0] at 1 year interval and earnings[1] through earnings[4] at a 5 year interval.

So with Invested value of 1000 and interest rate of 10%, it returns the following output for 5 years

Year1  = 1100
Year2  = 1210
Year3  = 1331
Year4  = 1464.1
Year5  = 1610.51

What I want is this

Year1  = 1100
Year5  = 1610.51
Year10 = 2593.74246
Year15 = 4177.248169
Year20 = 6727.499949

Upvotes: 3

Views: 860

Answers (2)

kylegill
kylegill

Reputation: 314

You could use a modulus on the years in your for loop to add only those years that are divisible by 5. Then add another or condition for the first year:

function EarningsCalculator (rate, investedValue) {

var earnings = {};
var currentState = investedValue;
var YEAR_INTERVAL = 5;
var YEARS_COMPOUNDING = 20;

for (var i = 1; i <= YEARS_COMPOUNDING; i++) {

        earning=currentState*rate;

        currentState = currentState + earning;
            if (i % YEAR_INTERVAL == 0 || i == 1) {
        earnings[i] = currentState;
    }
}

return earnings;
}

var earnings = [];
earnings = EarningsCalculator(.10,1000); 
console.log(earnings);

That should log the correct values to your object in the console.

One advantage of this is being able to change your yearly interval as a variable rather than hardcoding those values in an array for different periods of time.

JSFiddle: https://jsfiddle.net/kgill/zgmrtmhg/1/

Upvotes: 1

Nina Scholz
Nina Scholz

Reputation: 386883

You could use the formular for calculation the earnings.

function getPeriodicCompounding(p, r, t) {
    return Math.pow(r + 1, t) * p;
}

var originalPrincipalSum = 1000,
    interestRate = 0.1,
    times = [1, 5, 10, 15, 20]
    
times.forEach(function (time) {
    console.log(time, getPeriodicCompounding(originalPrincipalSum, interestRate, time));
});

Upvotes: 3

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