Workshop › 2048 › Step 11 of 26

Merge equal tiles

What we are doing

Two equal neighbours merge into one tile of double the value, and a tile made by a merge cannot merge again in the same move: [2, 2, 2, 2] becomes [4, 4, 0, 0], not [8, 0, 0, 0].

```js
if (tiles[i] === tiles[i + 1]) {
  result.push(tiles[i] * 2)
  gained += tiles[i] * 2
  i++ // the next tile was used up by this merge
} else {
  result.push(tiles[i])
}
```

What it means

• If a tile equals the next one, their sum goes into result and is added to gained.
• i++ inside the loop skips the next tile, which was used up by the merge. So a merged tile is never looked at again.
• Otherwise the tile is copied as it is. For the last tile tiles[i + 1] is undefined, never equal.

Your turn

In slideRow, replace result.push(tiles[i]) in the loop with the if ... else block.

Skills: Loops

← Slide a row Move left →

All steps

1. The board
2. Sixteen cells
3. A grid of numbers
4. A color for every number
5. Numbers on the tiles
6. Big numbers, smaller text
7. Find the empty cells
8. A new tile
9. Two tiles to start
10. Slide a row
11. Merge equal tiles
12. Move left
13. The arrow key
14. Only real moves count
15. Right is left, reversed
16. Up and down are columns
17. Score
18. Is there a move left?
19. Game over
20. Making 2048
21. Win and lose screens
22. Space to go on
23. Best score
24. Swipes
25. A tap is not a swipe
26. Build it yourself: undo