# Cash Register - help

Tell us what’s happening:
For some reason, the array “cid” is also being modified when I call the map method on it to assign the returned array to “resultingArray.” The “cid” array also has it’s values turned into 0. Can someone please explain why?

Edit: oh wait I think I know why. It’s because the reference to “cid” is getting passed into the anonymous function. I thought it was a copy of cid… BUT I wanna know why “origArr” also has its values turned into 0. It’s declared and defined before the map method is called.

``````

function checkCashRegister(price, cash, cid) {
let change = cash - price;
let total = 0;
for (let i = 0; i < cid.length; i++) {
total += cid[i][1];
}
if (total < change) {
return {status: "INSUFFICIENT_FUNDS", change: []};
}
if (total === change) {
return {status: "CLOSED", change: [...cid]};
}
let origArr = [...cid];
let resultArr = origArr.map(x => {
x[1] = 0;
return x;
});
let denom;
for (let i = origArr.length - 1; i >= 0; i--) {
switch (origArr[i][0]) {
case "ONE HUNDRED":
denom = 100;
break;
case "TWENTY":
denom = 20;
break;
case "TEN":
denom = 10;
break;
case "FIVE":
denom = 5;
break;
case "DOLLAR":
denom = 1;
break;
case "QUARTER":
denom = .25;
break;
case "DIME":
denom = .1;
break;
case "NICKEL":
denom = .05;
break;
case "PENNY":
denom = .01;
}
while (change - denom > 0 && origArr[i][1] > 0) {
change -= denom;
origArr[i][1] -= denom;
resultArr[i][1] += denom;
}
if (change === 0) {
return {status: "OPEN", change: resultArr.filter(x => x[1] !== 0)};
}
//console.log(resultArr);
}
return {status: "INSUFFICIENT_FUNDS", change: []};
}

checkCashRegister(19.5, 20, [["PENNY", 1.01], ["NICKEL", 2.05], ["DIME", 3.1], ["QUARTER", 4.25], ["ONE", 90], ["FIVE", 55], ["TEN", 20], ["TWENTY", 60], ["ONE HUNDRED", 100]]);
``````

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