Function keyDown

keyDown(key: string): boolean
Check if a key is currently held down.
Parameters
- key: string
  The key name (e.g. "ArrowLeft", "a", " " for space)
Returns boolean
True if the key is currently pressed
Example
```
if (sg.keyDown('ArrowRight')) { x += speed * dt; }
```
- Defined in input.ts:10