Workshop › Memory › Step 16 of 25

Two cards at a time

What we are doing

A turn is two cards. We keep the cards turned over this turn in a small array, opened, and refuse a third card while two are open.

```js
let opened // the cards turned over this turn (0, 1 or 2)

  opened = []

function flip(card) {
  if (!card || card.faceUp || opened.length === 2) return
  card.faceUp = true
  opened.push(card)
}
```

What it means

• opened starts empty in every new game.
• opened.length === 2 is one more reason to refuse: two cards are already showing.
• opened.push(card) remembers the card turned over.

Your turn

1. Under let cards, write let opened.
2. At the end of newGame, write opened = [].
3. In flip, add || opened.length === 2 to the if, and opened.push(card) at the end.

Skills: Game states, Arrays and objects

← One place for the rules Pair or no pair →

All steps

1. Get the canvas and the pen
2. The table
3. One card
4. A row of cards
5. Four rows
6. Every fruit twice
7. Cards that know themselves
8. A card's corner
9. Draw the cards from the list
10. Draw again and again
11. The face of a card
12. A fair shuffle
13. Which card is at a point?
14. Click to turn a card
15. One place for the rules
16. Two cards at a time
17. Pair or no pair
18. Count the moves
19. Show moves and pairs
20. All pairs found
21. Play again
22. A number that follows
23. Swap sides halfway
24. Animate the turn
25. Build it yourself: your best game