Workshop › 2048 › Step 15 of 26

Right is left, reversed

What we are doing

Do we need a second function for right? No: reverse the row, slide it left, reverse it back. Sliding a reversed row left is the same as sliding the original row right.

```js
  const reversed = direction === 'right'

    const line = [...board[i]]
    if (reversed) line.reverse()
    const { row } = slideRow(line)
    if (reversed) row.reverse()

const directions = { ArrowLeft: 'left', ArrowRight: 'right' }
```

What it means

• reversed is true for right.
• reverse() turns an array around in place: it changes the array itself. So we reverse a copy: [...board[i]] spreads the row's items into a new array.
• After sliding, the result is reversed back, and the table gets the right arrow.

Your turn

1. In move, under before, write the reversed line.
2. In the loop, change line to a copy and add the two reverse lines.
3. Add ArrowRight to the table.

Skills: Arrays and objects

← Only real moves count Up and down are columns →

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