Workshop › Mario-style Platformer › Step 10 of 37
Running needs to know which keys are held down right now, every frame. keys remembers it: a key goes true when
pressed and false when released.
```js
const keys = {}
document.addEventListener('keydown', (event) => {
keys[event.key] = true
})
document.addEventListener('keyup', (event) => {
keys[event.key] = false
})
```keys starts empty; keys[event.key] = true adds or sets a key named after the pressed key, e.g. keys.ArrowRight.keydown fires when a key goes down, keyup when it comes back up.let player write const keys = {}.function updatePlayer() { write the two listeners, with an empty line after them.Skills: Keyboard and mouse input