Workshop › Sudoku › Step 4 of 28

The puzzle's own digits

What we are doing

The digits the puzzle starts with are fixed. A second grid, given, remembers them: dark and bold. Digits you write later will be blue and thin.

```js
let given // given[r][c]: true for the puzzle's own digits, which cannot be changed

  given = grid.map((row) => row.map((d) => d !== 0))

      ctx.fillStyle = given[r][c] ? '#0f172a' : '#2563eb'
      ctx.font = (given[r][c] ? 'bold ' : '') + '26px sans-serif'
```

What it means

• grid.map((row) => row.map(...)) makes a grid of the same shape: true where the puzzle has a digit.
• The color and the font depend on it: condition ? a : b.

Your turn

1. Under let grid, write let given; in reset, work out given.
2. In draw, choose the color and the font from given.

Skills: Game states

← A puzzle from a string Keep drawing →

All steps

1. Nine by nine
2. Lines and boxes
3. A puzzle from a string
4. The puzzle's own digits
5. Keep drawing
6. The selected cell
7. Light up row, column and box
8. The same digit everywhere
9. Click to select
10. Move with the arrows
11. Write digits
12. The three rules in one loop
13. Show mistakes
14. Solved!
15. A clock
16. The solved message
17. Play again
18. The easiest cell
19. The solver
20. Random order
21. Invent a puzzle
22. A new puzzle every game
23. Hints
24. Best time
25. N for a new puzzle
26. A number pad
27. Tap the pad
28. Build it yourself: undo