calc.js

document.addEventListener('DOMContentLoaded', reset)
document.addEventListener("click", clicked);

 var display;
 var displayContent;
 var listNumbers;
 var listOperators;
 var calculatedNumber;

 function reset () {
   display = document.getElementById("display")
   displayContent = "";
   listNumbers = [];
   listOperators = [];
   updateDisplay();
 }
 function clicked(event){
   var buttonClicked = event.target;
   if (buttonClicked.classList.contains("number")){
       displayContent += buttonClicked.innerHTML;}
   else if (buttonClicked.classList.contains("operator")) {
     addCalculation(buttonClicked.id);}
   else{
     switch(buttonClicked.id) {
       case "decimal":
           if (!displayContent.includes(".")) displayContent += ".";
           break;
       case "clear":
           reset();
           break;
       case "clearentry":
           displayContent = "";
       case "equals":
           listNumbers.push(convertToNumber(display.value));
           displayContent = doCalculations();
           break; }
   }
   updateDisplay();
 }
 function addCalculation (operator) {
   listNumbers.push(convertToNumber(display.value));
   listOperators.push(operator);
   displayContent = "";
   updateDisplay();
 }
 function doCalculations () {
   console.log(listNumbers);
   console.log(listOperators);
   let num1 = listNumbers.splice(0,1);
   let num2 = listNumbers.splice(0,1);
   let operator = listOperators.splice(0,1);
   console.log(num1+" "+operator+" "+num2)
   let result = doOperation(num1, num2, operator);
 if (listOperators.length==0) {
   return result;}
 else {
   listNumbers.unshift(result);
   return doCalculations ();}
}
function doOperation (num1, num2, operator) {
if (operator=="add") {
  return Number(num1)+Number(num2);}
  else if (operator=="subtract") {
    return num1 - num2; }
    else if (operator=="multiply") {
      return num1 * num2; }
      else if (operator=="divide") {
        return num1/num2; }
      }
function convertToNumber(n) {
   let int = parseInt(n)
   if (isNaN(int)) {
     return 0;}
   return int;
 }
function updateDisplay () {
   display.value = displayContent;
 }