Workshop › Missile Command-style Defense › Step 27 of 35

The end of a wave

What we are doing

A wave is over when nothing is left to launch, nothing is in the air and no explosion is still going. You get a bonus, a short pause, then the next wave.

```js
let state // 'playing', 'between' (a pause after a wave) or 'over'
let pause

  state = 'playing'

  if (state === 'between') {
    pause -= 1
    if (pause <= 0) nextWave()
    return
  }

  if (toLaunch === 0 && incoming.length === 0 && blasts.length === 0) {
    // Bonus for every city still standing and every interceptor left.
    score += cities.filter((c) => c.alive).length * 100 + ammo * 5
    state = 'between'
    pause = 90
  }
```

What it means

• nextWave sets the state to 'playing'.
• Between waves, update only counts pause down; at 0 the next wave starts. return skips everything else.
• At the end of update: when the wave is finished, add the bonus, switch to 'between' and pause 90 frames.

Your turn

1. Under let score write let state (with its comment) and let pause.
2. At the end of nextWave, write state = 'playing'.
3. At the very top of update, write the between block, followed by an empty line.
4. At the end of update, under incoming = incoming.filter(...), leave an empty line and write the wave-end block.

Skills: Game states

← Each wave is harder The end →

All steps

1. Six cities to protect
2. Your missile base
3. Draw again and again
4. Cities that can fall
5. Rubble
6. Move towards a point
7. Launch an enemy missile
8. One missile a second
9. Missiles on their way
10. Smoke trails
11. Impact
12. Fire an interceptor
13. Click the sky
14. Interceptors fly
15. An explosion that grows and shrinks
16. Explode on arrival
17. Draw the explosions
18. Impacts explode too
19. Caught in the blast
20. Chain reactions
21. Only your explosions count
22. Points for every missile
23. Show the score
24. Limited ammo
25. Waves
26. Each wave is harder
27. The end of a wave
28. The end
29. Play again
30. Wave, ammo and messages
31. Launch from anywhere
32. Some missiles will split
33. Split into three
34. A high score
35. Build it yourself: a crosshair