Tip calculator using plain HTML/CSS/JS

function updateDOM (){
    
        let billValue = billInput.value;
        let tipValue = document.querySelector('input[name="tip"]:checked').value;
        let numberOfPeople = peopleInput.value;

        let resultTip = calculateTip(billValue, tipValue, numberOfPeople);
        let resultTotal = calculateTotal(billValue, tipValue, numberOfPeople);

        resultTipElt.innerText = `${resultTip}`;
        resultTotalElt.innerText = `${resultTotal}`;
}

function inputHandler (e){
      e.stopPropagation;
      if (resetButton.getAttribute('disabled') != null) {
        resetButton.removeAttribute('disabled');
      }
      let inputIsEmpty = inputsEmpty();
      if ((inputIsEmpty == true)) {
        console.log('input empty');
        resetButton.setAttribute('disabled',"");
      }
      let inputIsValid = checkInputs();
      if (inputIsValid == true) {
           updateDOM()
      }
}

function clickHandler (e){
      e.stopPropagation;
      let inputIsValid = checkInputs();
      if (inputIsValid == true) {
           updateDOM()
      }
}

document
  .querySelectorAll("input")
  .forEach(element => {
    element.addEventListener('input',inputHandler )
    element.addEventListener('click',clickHandler )
});

You can convert the repeating code to functions