Workshop › Space Invaders-style › Step 5 of 21

Fire

What we are doing

Space fires a bullet from the cannon. Bullets live in a list, each a small box starting just above the ship.

```js
const BULLET_SPEED = 8
let bullets = []

function shoot() {
  bullets.push({ x: ship.x + SHIP_W / 2 - 2, y: ship.y - 12, w: 4, h: 12 })
}

  if (event.key === ' ') shoot()
```

What it means

• A bullet is 4×12, centered on the cannon: ship.x + SHIP_W / 2 - 2.
• shoot adds it to bullets; Space calls shoot.

Your turn

1. Under SHIP_SPEED, write BULLET_SPEED; under ship, write let bullets = [].
2. Under keys, write shoot; in keydown, fire on Space.

Skills: Keyboard and mouse input, Arrays and objects

← Stay on screen Bullets fly →

All steps

1. The ship
2. The game loop
3. Move the ship
4. Stay on screen
5. Fire
6. Bullets fly
7. A short reload
8. The invaders
9. The march
10. Hit!
11. Score
12. They shoot back
13. Bombs fall
14. Lives
15. Game over
16. Best score
17. A wave in a function
18. Play again
19. Waves
20. Faster and faster
21. Build it yourself: an extra life