function IRR(cashFlows, estimatedResult) {  var result = "isNAN";  if (cashFlows != null && cashFlows.length > 0) {  // check if business startup costs is not zero:  if (cashFlows[0] != 0) {  var noOfCashFlows = cashFlows.length;  var sumCashFlows = 0;  // check if at least 1 positive and 1 negative cash flow exists:  var noOfNegativeCashFlows = 0;  var noOfPositiveCashFlows = 0;  for (var i = 0; i < noOfCashFlows; i++) {  sumCashFlows += cashFlows[i];  if (cashFlows[i] > 0) {  noOfPositiveCashFlows++;  } else {  if (cashFlows[i] < 0) {  noOfNegativeCashFlows++;  }  }  }  // at least 1 negative and 1 positive cash flow available?  if (noOfNegativeCashFlows > 0 && noOfPositiveCashFlows > 0) {  // set estimated result:  var irrGuess = 0.1; // default: 10%  if (!isNaN(estimatedResult)) {  irrGuess = estimatedResult;  if (irrGuess <= 0) {  irrGuess = 0.5;  }  }  // initialize first IRR with estimated result:  var irr = 0;  if (sumCashFlows < 0) { // sum of cash flows negative?  irr = -irrGuess;  } else { // sum of cash flows not negative  irr = irrGuess;  }  // iteration:  // the smaller the distance, the smaller the interpolation  // error  var minDistance = 1e-15;  // business startup costs  var cashFlowStart = cashFlows[0];  var maxIteration = 100;  var wasHi = false;  var cashValue = 0;  for (var i = 0; i <= maxIteration; i++) {  // calculate cash value with current irr:  cashValue = cashFlowStart; // init with startup costs  // for each cash flow  for (var j = 1; j < noOfCashFlows; j++) {  cashValue += cashFlows[j] / Math.pow(1 + irr, j);  }  // cash value is nearly zero  if (Math.abs(cashValue) < 0.01) {  result = irr;  break;  }  // adjust irr for next iteration:  // cash value > 0 => next irr > current irr  if (cashValue > 0) {  if (wasHi) {  irrGuess /= 2;
                      }  irr += irrGuess;  if (wasHi) {  irrGuess -= minDistance;  wasHi = false;  }  } else {// cash value < 0 => next irr < current irr  irrGuess /= 2;  irr -= irrGuess;  wasHi = true;  }  // estimated result too small to continue => end  // calculation  if (irrGuess <= minDistance) {  result = irr;  break;  }  }  }  }  }  return result;
}