Workshop › Snake › Step 17 of 28

Never put food on the snake

What we are doing

Random food can land on the snake's body. We keep picking until the cell is free.

```js
function placeFood() {
  do {
    food = { x: Math.floor(Math.random() * COLS), y: Math.floor(Math.random() * ROWS) }
  } while (snake.some((part) => part.x === food.x && part.y === food.y))
}
```

What it means

• do { ... } while (condition) runs the body once, then again as long as the condition is true.
• snake.some(test) is true if at least one part passes the test: here, "is this part on the food cell?".

Your turn

Wrap the line inside placeFood in do { ... } while (...) as shown.

Skills: Arrays and objects, Loops

← Eat and grow A table of turns →

All steps

1. Find the canvas
2. Get the pen
3. Paint the board
4. Think in cells
5. Keep the position in a variable
6. A function that draws
7. A function that moves
8. The game loop
9. Slow it down
10. A direction to move in
11. Steer with the arrow keys
12. A body made of a list
13. Move the whole body
14. Pick a spot for the food
15. Draw the food
16. Eat and grow
17. Never put food on the snake
18. A table of turns
19. No U-turns
20. Crash into the walls
21. Crash into yourself
22. The game over message
23. Show the score
24. One function that starts a game
25. Play again with Space
26. Remember the best score
27. Speed up as you grow
28. Build it yourself: through the walls