Нужно привязать клавижу клавиатуры к button с помощью javascript

const btn1 = document.getElementById('btn-1'); 
const btn2 = document.getElementById('btn-2'); 
const btn3 = document.getElementById('btn-3'); 
 
btn1.addEventListener('click', () => alert(1)); 
btn2.addEventListener('click', () => alert(2)); 
btn3.addEventListener('click', () => alert(3)); 
 
window.addEventListener('keypress', event => { 
  switch (event.keyCode) { 
    case 49: btn1.click(); 
      break; 
    case 50: btn2.click(); 
      break; 
    case 51: btn3.click(); 
      break; 
  } 
});

<button id="btn-1" type="button">1</button> 
<button id="btn-2" type="button">2</button> 
<button id="btn-3" type="button">3</button>