Prompt: tackling floating-point imprecision with the CashAmount class

cashamount class

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

//converts amount to pennies
  totalInPennies() {
    return this.value * 100;
  }

//adds amount to value
  addDoubleAmount(addedValue) {
    return this.value = ((this.value * 100) + (addedValue * 100)) / 100;
  }

  //returns object with denominations from 100 to pennies
  quantityOfEachDenomination() {
    let dollars = [['hundreds', 100], ['fifties', 50], ['twenties', 20], ['tens', 10], ['fives', 5], ['ones', 1]];
    let cents = [['quarters', 25], ['dimes', 10], ['nickels', 5], ['pennies', 1]]
    var billNCents = this.toDoubleString().split('.').map(function(money){return Number(money)});
    var counter = 0;
    var result = {};
    if (billNCents.length > 1) {
      billNCents[1] = (this.value - billNCents[0]) * 100
      var centValue = billNCents[1];
      for(var i = 0; i < cents.length; i++) {
        result[cents[i][0]] = 0;
        while(centValue - cents[i][1] > 0 ) {
          result[cents[i][0]]++;
          centValue = centValue - cents[i][1]
        }
      }
    }
    var dollarValue = billNCents[0];
    for(var j = 0; j < dollars.length; j++) {
      result[dollars[j][0]] = 0;
      while(dollarValue - dollars[j][1] > 0 ) {
        result[dollars[j][0]]++;
        dollarValue = dollarValue - dollars[j][1]
      }
    }
    return result;
  }

  //returns value
  toDouble() {
    return this.value;
  }

  //returns string of value
  toDoubleString() {
    return String(this.value);
  }

}


// test

const cash = new CashAmount(0.10);
cash.addDoubleAmount(0.20);
console.log(cash.totalInPennies() === 30);