app.js

const screenDisplay = document.querySelector(".screen");
const buttons = document.querySelectorAll("button");

let calculation = [];
let accumulativeCalculation;
localStorage.getItem(JSON.stringify("calculation"));

function calculate(button) {
  const value = button.textContent;

  if (value === "CLEAR") {
    calculation = [];
    screenDisplay.textContent = ".";
  } else if (value === "=") {
    screenDisplay.textContent =
      Math.round(eval(accumulativeCalculation) * 100) / 100;
    JSON.parse(localStorage.setItem("calculation", accumulativeCalculation));
  } else {
    calculation.push(value);
    accumulativeCalculation = calculation.join("");
    screenDisplay.textContent = accumulativeCalculation;
  }
}

buttons.forEach((button) =>
  button.addEventListener("click", () => calculate(button)),
);