Use a loop for the button click listeners

[oparkins]

I would have recommended using a loop to add all of those event listeners. It would be something like this (untested:

const buttons = [btnOne, btnTwo, btnThree, ...];

for (const [index, button] of buttons.entries()) {
    button.addEventListener('click', () => {
        calculatorDisplayContent.textContent += index.toString();
        calculatorDisplay.appendChild(calculatorDisplayContent);
        checkIfEvaluationIsSolvable();
        phaseInAllExpressions();
        checkForOverflow();
    });
}

That should make the code more readable and maintainable.

[snack-boomz]

So this is something I knew in my head from basic principles I've learned in the past (DRY... don't repeat yourself); but I hadn't figured out a way to implement it in code yet. Looks like this is exactly what I needed to figure this out!

Thanks!