CashAmount {Accurate}

class CashAmount {
  constructor(amount) {
    this.amount = amount;
  }
}

CashAmount.prototype.totalInPennies = function() {
  var pennies = this.amount * 100;
  return pennies;
};
CashAmount.prototype.addDoubleAmount = function(doubleAmount) {
  this.amount = this.amount * 100;
  this.amount += (doubleAmount * 100);
  this.amount /= 100;
  
  return this.amount;
};
CashAmount.prototype.quantityOfEachDenomination = function() {
  var denominations = [
      'thousands',
      'hundreds',
      'fifties',
      'twenties',
      'tens',
      'fives',
      'ones',
      'quarters',
      'dimes',
      'nickels',
      'pennies'
    ];
  var amountArray = (this.amount * 100 + '').split('');
  var storage = {};
  while(amountArray.length > 0) {
    var popNumber = amountArray.pop();
    var popString = denominations.pop();
    storage[popString] = popNumber;
  }
  return storage;
};
CashAmount.prototype.toDouble = function() {
  return this.amount;
};
CashAmount.prototype.toDoubleString = function() {
  return this.amount.toFixed(2);
};