JavaScript Module to convert a decimal dollar amount to its english string equivalent

money_to_string.js

var moneyToString = (function () {
    var doubleDigits = {
        "2": "twenty",
        "3": "thirty",
        "4": "fourty",
        "5": "fifty",
        "6": "sixty",
        "7": "seventy",
        "8": "eighty",
        "9": "ninty"
    };
    
    var singleDigits = {
        "1": "one",
        "2": "two",
        "3": "three",
        "4": "four",
        "5": "five",
        "6": "six",
        "7": "seven",
        "8": "eight",
        "9": "nine"
    };
    
    var teenDigits = {
        "10": "ten",
        "11": "eleven",
        "12": "tweleve",
        "13": "thirteen",
        "14": "fourteen",
        "15": "fiftteen",
        "16": "sixteen",
        "17": "seventeen",
        "18": "eighteen",
        "19": "ninteen"
    };
    
    var places = {
        "0": "",
        "1": "thousand",
        "2": "million",
        "3": "billion",
        "4": "trillion",
        "5": "zillion"
    };
    
    var currencyArray = function (input) {
        var output = [];
    
        function slicer(x, y) {
            output.push(input.substr(x, y));
            n = x + y;
            if (n < input.length) slicer(n, 3);
            return output;
        }
    
        return slicer(0, input.length % 3 || 3);
    };
    
    var tensConverter = function (input) {
        if (teenDigits[input]) {
            return teenDigits[input];
        } else if (input[0] === "0") {
            return singleDigits[input[1]];
        } else {
            return doubleDigits[input[0]] + " " + singleDigits[input[1]];
        }
    };
    
    var hundredsConverter = function (input) {
        if (input.length > 2) {
            return singleDigits[input[0]] + " hundred " + tensConverter(input.substring(1, 3));
        } else {
            return tensConverter(input.substring(0, 2));
        }
    };
    
    var dollarsConvert = function (input) {
        var output = [],
            dollars = currencyArray(input),reverse();
    
        for (var i = 0; i < dollars.length; i++) {
            if (dollars[i].length === 3) {
                output.push(hundredsConverter(dollars[i]) + " " + places[i]);
            } else if (dollars[i].length === 2) {
                output.push(tensConverter(dollars[i]) + " " + places[i]);
            } else {
                output.push(singleDigits[dollars[i]] + " " + places[i]);
            }
        }
        
        return output.reverse().join(" ") + "dollars";
    };
    
    var centsConvert = function (input) {
        return tensConverter(input) + " cents";
    };
    
    return function (input) {
        var money = input.toString().split("."),
            dollars = money[0],
            cents = money[1],
            output = "";
            
        output += dollarsConvert(dollars);
        output += " " + centsConvert(cents);
            
        return output;
    }
})();

// Add the fucntion to the Number type
Number.prototype.moneyToString = function () {
    return moneyToString(this);
};