Workshop › Connect Four › Step 33 of 38

The computer's turn

What we are doing

Yellow is now the computer. When the turn passes to it, it waits half a second (30 frames), so you can see what happened, then plays computerMove(). thinking counts the frames down in update.

```js
let thinking // frames until the computer moves

  thinking = 0

    turn = 3 - turn
    if (turn === 2) thinking = 30

    return
  }
  if (!winner && turn === 2) {
    thinking -= 1
    if (thinking <= 0) play(computerMove())
  }
```

What it means

• land starts the countdown when the turn passes to the computer.
• In update, return after the falling disc means the countdown waits while a disc falls.
• While the game is on and it is the computer's turn, thinking goes down by 1 each frame; at 0 the computer plays.

Your turn

1. Under let hoverCol write let thinking; in reset, under falling = null, write thinking = 0.
2. In land, under turn = 3 - turn, start the countdown.
3. In update, add return at the end of the falling block and the countdown after it.

Skills: Game states, The game loop

← Prefer the middle Only on your turn →

All steps

1. A dark background
2. A drawing function
3. The blue board
4. One hole
5. A whole row
6. All 42 holes
7. The board in memory
8. Discs in their colors
9. Draw every frame
10. Where does the disc land?
11. Play a column
12. Taking turns
13. Click to play
14. The next disc
15. Whose turn?
16. Playing with the keyboard
17. Keys 1 to 7
18. A disc on its way
19. Gravity
20. Watch it fall
21. Inside the board?
22. Walking along a line
23. Four in a row?
24. We have a winner
25. Circle the four
26. Who won?
27. A draw
28. Play again
29. Try a move and take it back
30. Win, or block
31. Don't help the player
32. Prefer the middle
33. The computer's turn
34. Only on your turn
35. You and the computer
36. Counting wins
37. Show the score
38. Build it yourself: the loser starts