String manipulation of currency to acquire penny amount

currencyToPennies.js

function currencyToPennies (currency) {
  // ensure string
  var strCurrency = currency.toString();
  
  // ignore any character that's not part of a number
  var wholeAmount = strCurrency.replace(/[^0-9.]/g, '');
  
  // locate decimal
  var decimalIndex = wholeAmount.indexOf('.');
  var normalizedAmount;
  if (decimalIndex > 0) {
    // truncate to 2 decimal places
    normalizedAmount = wholeAmount.slice(0, decimalIndex + 3);
  } else {
    // whole number, concat decimal value
    normalizedAmount = wholeAmount + '.00';
  }
  
  // drop decimal (leaves total pennies)
  var pennyAmount = normalizedAmount.replace(/[^0-9]/g, '');
  
  // Negative Number format
  if (strCurrency.indexOf('(') > -1 && strCurrency.indexOf(')') > -1) {
    pennyAmount *= -1;
  }
  
  return parseInt(pennyAmount);
}