formatMoney.js

document.addEventListener("DOMContentLoaded", function() {

/**
 *      FORMAT MONEY
 *
 *  @param  {string|integer} rawNumber	        Number to be formatted.
 *  @param  {integer}	     fractionDigits     how many digits will be in the decimal section
 *  @param  {string} 	     decimalSign        sign of the separator of decimal section
 *  @param  {string} 	     thousandsSeparator sign of the separator of thousands section
 *
 *  @return {string}		 formatted number
 */
function formatMoney(rawNumber, fractionDigits, decimalSign, thousandsSeparator) {

	// If the number parameter is omitted, it returns an error message and returns false.
	if ( typeof (rawNumber) === "undefined" ) {
		console.error("formatToMoney Function -> A number must be given as the first parameter of the formatToMoney function.");
		return false;
	}
	// decimalSign and thousandsSeparator cannot be the same value.
	if(decimalSign == thousandsSeparator) {
		console.error("formatToMoney Function -> DecimalSign and ThousandsSeparator cannot be the same value.");
		return false;
	}

	// declare variables.
	var intPartStr, decPartStr, intPartNum, decPartNum, rawNumberStr, neg, firstSirstSeparatorIndex;

	// default value of fraction digits = 2
	fractionDigits = isNaN(fractionDigits = Math.abs(fractionDigits)) ? 2 : fractionDigits;

	// default value of decimal sign = ","
	decimalSign = typeof (decimalSign) === "undefined" ? "," : decimalSign;

	// default value of thousands separator = "."
	thousandsSeparator = typeof (thousandsSeparator) === "undefined" ? "." : thousandsSeparator;

	// maybe another type
	rawNumberStr = rawNumber.toString();

	// purify the number from thousandsSeparators. RegExp much slower than string search.
	if(rawNumberStr.search(thousandsSeparator) != -1) {
		rawNumberStr = rawNumberStr.split(thousandsSeparator).join("");
	}

	// take digit and fraction of the number
	if(rawNumberStr.search(decimalSign) != -1) {
		if (rawNumberStr.substr(-1) == decimalSign) {
			intPartStr = rawNumberStr;
			decPartStr = "0".repeat(fractionDigits);
		} else {
			rawNumberStr_splitted = rawNumberStr.split(decimalSign);
			intPartStr = rawNumberStr_splitted[0];
			decPartStr = rawNumberStr_splitted[1];
		}
	} else {
		intPartStr = rawNumberStr;
		decPartStr = "0".repeat(fractionDigits);
	}

	intPartNum = parseInt(intPartStr);


	// number -> positive or negative.
	neg = intPartNum < 0 ? "-" : "";

	intPartNum = Math.abs(intPartNum);

	intPartStr = intPartNum.toString();

	// an interesting rounding attempt :)
	decPartStr = ( (decPartStr.length > fractionDigits) && (parseInt( decPartStr.substr(fractionDigits, 1) ) >= 5) ) ? decPartStr.substr(0, fractionDigits - 1) + (parseInt( decPartStr.substr(fractionDigits - 1, 1) ) + 1).toString() : decPartStr;


	// Thousands Separator first index.
	firstSeparatorIndex = (firstSeparatorIndex = intPartStr.length) > 3 ? firstSeparatorIndex % 3 : 0;

	// RETURN
	return neg +

	(firstSeparatorIndex ? intPartStr.substr(0, firstSeparatorIndex) + thousandsSeparator : "") +

	intPartStr.substr(firstSeparatorIndex).replace(/(\d{3})(?=\d)/g, "$1" + thousandsSeparator) +

	( (fractionDigits) ? decimalSign + decPartStr.substr(0, fractionDigits) : "");

}

});