numberToMoney.js

function numberToMoney(fixed = 2, value) {
	if (!value || typeof value != 'number') {
  		throw new Error("´value´ is not set");
  	}

	let formatted = value.toFixed(fixed).replace('.', ',').split(',');
	let final = [];

	if (formatted[0].length > 3) {
		for (let i = formatted[0].length - 1; i >= 0; i--) {
    			final.push(formatted[0][i]);

      			if ((formatted[0].length - i) % 3 == 0 && (formatted[0].length - i) != formatted[0].length) {
				final.push('.');
			}
		}
		final = final.reverse().join("").concat(',' + formatted[1]);
	} else {
		final = formatted[0].concat(',' + formatted[1]);	
	}

	return final;
}

console.log(numberToMoney(4, 1000));