Build a Cash Register

JavaScript
1

Hi there!, I’m having an issue with 2 lasts tests:

  • When price is 19.5, the value in the #cash element is 20, cid is [["PENNY", 0.5], ["NICKEL", 0], ["DIME", 0], ["QUARTER", 0], ["ONE", 0], ["FIVE", 0], ["TEN", 0], ["TWENTY", 0], ["ONE HUNDRED", 0]], and the #purchase-btn element is clicked, the value in the #change-due element should be "Status: CLOSED PENNY: $0.5".

  • Failed:When price is less than the value in the #cash element, total cash in drawer cid is equal to change due, and the #purchase-btn element is clicked, the value in the #change-due element should be "Status: CLOSED" with change due in coins and bills sorted in highest to lowest order.

I’m very confused and stucked as well

Here’s my codes:

let price = 19.5;
let cid = [
  ["PENNY", 1.01],
  ["NICKEL", 2.05],
  ["DIME", 3.1],
  ["QUARTER", 4.25],
  ["ONE", 90],
  ["FIVE", 55],
  ["TEN", 20],
  ["TWENTY", 60],
  ["ONE HUNDRED", 100]
];

const currencyUnit = {
  "PENNY": 0.01,
  "NICKEL": 0.05,
  "DIME": 0.1,
  "QUARTER": 0.25,
  "ONE": 1,
  "FIVE": 5,
  "TEN": 10,
  "TWENTY": 20,
  "ONE HUNDRED": 100
};

function checkCashRegister(price, cash, cid) {
  let changeDue = Math.round((cash - price) * 100) / 100;
  const totalCid = Math.round(cid.reduce((sum, [, amount]) => sum + amount, 0) * 100) / 100;

  if (totalCid < changeDue) {
    return { status: "INSUFFICIENT_FUNDS", change: [] };
  }

  if (totalCid === changeDue) {
    return { status: "CLOSED", change: cid };
  }

  const change = [];
  const reversedCid = [...cid].reverse();

  for (let [unit, amount] of reversedCid) {
    const unitValue = currencyUnit[unit];
    let unitTotal = 0;

    while (changeDue >= unitValue && amount > 0) {
      changeDue = Math.round((changeDue - unitValue) * 100) / 100;
      amount -= unitValue;
      unitTotal += unitValue;
    }

    if (unitTotal > 0) {
      change.push([unit, unitTotal]);
    }
  }

  if (changeDue > 0) {
    return { status: "INSUFFICIENT_FUNDS", change: [] };
  }

  return { status: "OPEN", change: change };
}

document.getElementById('purchase-btn').addEventListener('click', function() {
  const cashInput = parseFloat(document.getElementById('cash').value);
  const changeDueElement = document.getElementById('change-due');

  if (cashInput < price) {
    alert("Customer does not have enough money to purchase the item");
    changeDueElement.textContent = "";
    return;
  }

  if (cashInput === price) {
    changeDueElement.textContent = "No change due - customer paid with exact cash";
    return;
  }

  const result = checkCashRegister(price, cashInput, cid);
  let output = `Status: ${result.status}`;

  if (result.status === "CLOSED") {
    output += " " + result.change.map(([unit, amount]) => `${unit}: $${amount.toFixed(2)}`).join(' ');
  } else if (result.status === "OPEN") {
    output += " " + result.change.map(([unit, amount]) => `${unit}: $${amount.toFixed(2)}`).join(' ');
  }

  changeDueElement.textContent = output.trim();
});
2

Have you tried testing the first failing testcase yourself? What output is placed in the #change-due element? Does it match the expectation?

3

I went ahead and tested the first failing test case. Here’s what I did:

[
  ["PENNY", 1.01],
  ["NICKEL", 2.05],
  ["DIME", 3.1],
  ["QUARTER", 4.25],
  ["ONE", 90],
  ["FIVE", 55],
  ["TEN", 20],
  ["TWENTY", 60],
  ["ONE HUNDRED", 100]
]

I don’t know why the output didn’t match the expectation.

5

this doesn’t match the testcase though?

6

Definitely,… Could you please provide any guidance on what might be causing this discrepancy?

7

you haven’t answered me yet? I was wondering if you had tested your code with the specific testcase that was failing?
If yes, what value was getting printed to #change-due?
Was it the same as the testcase expected?

8

I tested the code, and I’m happy to report that my tests worked. I’ve fixed the bug, and now the output in #change-due matches the expected result.