numberToTextFormatter.js

var ones = ['','one','two','three','four','five','six','seven','eight','nine','ten','eleven','twelve','thirteen','fourteen','fifteen','sixteen','seventeen','eighteen','nineteen'];	
var tens = ['','ten','twenty','thirty','forty','fifty','sixty','seventy','eighty','ninety'];	
var oneMillion = 1000000;
var oneBillion = 1000000000;

var format = function(input){	
	if (input < 19){
		return ones[input];	
	} else if (input < 100) {
		var amountOfTens = Math.floor(input/10);
		input = input - amountOfTens * 10;
		var tensText = tens[amountOfTens];
		var restOfText = format(input);
		if(restOfText.length > 0){
			restOfText = ' ' + restOfText;
		}
		return tensText + restOfText;
	} else if (input < 1000) {
		var amountOfHundreds = Math.floor(input/100);
		input = input - amountOfHundreds * 100;
		var hundredsText = ones[amountOfHundreds] + ' hundred';
		var restOfText = format(input);
		if(restOfText.length > 0){
			restOfText = ' and ' + restOfText;
		}
		return hundredsText + restOfText;
	} else if (input < oneMillion) {
		var amountOfThousands = Math.floor(input/1000);
		input = input - amountOfThousands * 1000;
		return format(amountOfThousands) + ' thousand ' + format(input);
	} else if (input < oneBillion) {
		var amountOfMillions = Math.floor(input/oneMillion);
		input = input - amountOfMillions * oneMillion;
		return format(amountOfMillions) + ' million ' + format(input);
	}
}

module.exports = {format: format};