On keyup event, when shift + key released , shift before key , event.key not reflects key

Question

In javascript ,onkeyup event, when I press shfit + key , then release the shift before the key, I don't get the event.key for the key , instead I get "shift".
Is there a way to get the event.key for the key ?

Answer 1

Key up triggers the moment a key is released. It's impossible to release two keys at the same time but it is possible to press them at the same time:

var keysPressed = []

window.document.addEventListener("keydown", (event) => {
  if (keysPressed.indexOf(event.key) < 0) {
    keysPressed.push(event.key)
  }
});

window.document.addEventListener("keyup", (event) => {
  if (keysPressed.length) {
    // Show which keys where pressed
    console.log(keysPressed)
  }

  // Empty array 
  keysPressed = []
});

Answer 2

Remember pressed keys in a set (this prevents registering repeating keydowns):

const pressedKeys = new Set;

document.addEventListener('keydown', e => pressedKeys.add(e.key));
document.addEventListener('keyup', e => {
  pressedKeys.delete(e.key);
  e.key === 'Shift' && pressedKeys.size && console.log('Still pressed:', ...pressedKeys);
  pressedKeys.clear();
});