Algorithm Exact Change inaccurate output!

Exact Change https://www.freecodecamp.com/challenges/exact-change

Firefox 47.0 Windows 10

function checkCashRegister(price, cash, cid) {
  var change = cash - price,
      denom = [
        ["ONE HUNDRED", 100.00],
        ["TWENTY", 20.00],
        ["TEN", 10.00],
        ["FIVE", 5.00],
        ["ONE", 1.00],
        ["QUARTER", 0.25],
        ["DIME", 0.10],
        ["NICKEL", 0.05],
        ["PENNY", 0.01]
      ],
      register = cid.reduce(function(acc, curr) {
        acc.TOTAL += curr[1];
        acc[curr[0]] = curr[1];
        return acc;
      }, {"TOTAL": 0});


  // Here is your change, ma'am.

  if (register.TOTAL < change) {
    return "Insufficient Funds";
  } else if (register.TOTAL === change) {
    return "Closed";
  }

  var changeDue = [];
  for (var i = 0; i < denom.length; i++) {
    var currLeft = register[denom[i][0]],
        val = 0;
    while (change >= denom[i][1] && currLeft > 0) {
      change -= denom[i][1];
      currLeft -= denom[i][1];
      val += denom[i][1];
      change = Math.round(change * 100) / 100;
    }


    if (val > 0) {
      changeDue.push([denom[i][0], val]);
    }
  }

  if (change > 0) {
    return "Insufficient Funds";
  }

  return changeDue;

}

checkCashRegister(1, 2.05, [["PENNY", 0], ["NICKEL", 0], ["DIME", 0.30], ["QUARTER", 0.75], ["ONE", 1], ["FIVE", 0], ["TEN", 0], ["TWENTY", 0], ["ONE HUNDRED", 0]]); 

I passed all the FCC’s test cases. However, for the input above, output should be [[“DIME”, 0.30], [“QUARTER”, 0.75]] instead of “Insufficient Fund!”.

Similarly, for checkCashRegister(1, 6.05, [[“PENNY”, 0], [“NICKEL”, 0], [“DIME”, 0.30], [“QUARTER”, 0.75], [“ONE”, 1], [“FIVE”, 1], [“TEN”, 0], [“TWENTY”, 0], [“ONE HUNDRED”, 0]]); output should be [[“DIME”, 0.30], [“QUARTER”, 0.75], [“FIVE”, 1]].

I looked through FCC wiki page for the solution code and still got the same issue. I’m still trying to solve this challenge taking into account the above cases though.

[dskloet]

Instead you could make it explicit in the problem statement that the cashier will always try the maximum amount of each denomination and may fail to give change even though it is possible. “Insufficient funds” would have to be changed to “Failed to give change” or something.

[BKinahan]

@blueirisss That is indeed more reasonable! It is certainly realistic and does require a more complex solution.

So the question up for discussion is whether a test case should be added to make the challenge more complex and difficult in order to make it a more accurate approximation of the problem represented.

At this point in the course, is it reasonable to expect users to learn how to generate the various possible combinations of change to see if it can be paid correctly, rather than simply attempting to pay as much as possible with the highest denominations downward?