I am trying to create a calculator and I am unable to calculate negative numbers because my current logic splits displayValue using regular expressions to separate numbers and operators into displayArray.

Here is my code:

`// Initialize variables
let displayValue = '';
let displayArray = [];

const screenDiv = document.getElementById('screen');
const numberButtons = document.querySelectorAll('.number');
const operatorButtons = document.querySelectorAll('.operator');

// Event listeners for number buttons
numberButtons.forEach(button => {
    button.addEventListener('click', () => {
        displayValue += button.textContent;
        displayArray = displayValue.split(/([+-*/])/);
        const [firstNumber, operator, secondNumber] = displayArray;

        if (displayArray.length === 3) {
            screenDiv.textContent = secondNumber;
        } else {
            screenDiv.textContent = firstNumber;
        }

        if (firstNumber === '0') {
            displayValue = '';
        }
    });
});

// Event listeners for operator buttons
operatorButtons.forEach(button => {
    button.addEventListener('click', () => {
        if (displayArray.length === 3) {
            displayValue = operate(); // Assuming operate() is a function to perform the operation
            screenDiv.textContent = displayValue;
            displayValue += button.textContent;
        } else {
            displayValue += button.textContent;
        }
    });
});

`