Hiding the 0 that shows when a user presses the AC button on my calculator

I’ve added an AC button to my JS calculator which resets the variables and displays 0 in the displayArea.

However when the user starts typing their first number the 0 stay’s so it shows 03 instead of 3 etc – this doesn’t impact the calculation.

I’ve tried to remove this using parseInt and an IF statement however it doesn’t seem to work.

My best attempt so far is:

<p id="result-display">    </p>
let displayArea = document.getElementById('result-display');

else if (displayArea.innerHTML = 0) {
        buttonNumber = Number(e.target.innerText);
        displayValue = buttonNumber;
        displayArea.innerHTML = parseInt(displayArea.innerHTML += displayValue);
        }

If I change the 0 to a string e.g. ‘0’ it works but then also stops the user entering multiple number values e.g. 56 would show as 5 etc.

My JSFiddle is: https://jsfiddle.net/mh85skxv/3/