Workshop › Conway's Game of Life › Step 18 of 32

Running or not

What we are doing

We want to look at a pattern before it runs. A variable playing says whether the world is running; it starts as false, and update only steps while it is true.

```js
let playing

  playing = false

  if (playing && frames % SPEED === 0) step()
```

What it means

• playing is true or false; reset sets it to false, so a new world waits.
• playing && ... in update: step only when playing and it is time.

Your turn

1. Under let generation write let playing.
2. In reset, under randomize(), write playing = false.
3. In update, add playing && at the start of the condition.

Skills: Game states

← Let it live One place for the buttons →

All steps

1. The board
2. Measure the grid
3. One living cell
4. A function that draws
5. The world in memory
6. Draw every living cell
7. A random soup
8. Count the neighbours
9. Four rules
10. Draw again and again
11. Next generation with N
12. Count the generations
13. Show the generation
14. A world without edges
15. Count the living
16. A generation every few frames
17. Let it live
18. Running or not
19. One place for the buttons
20. Space to play, N to step
21. Clear and shuffle
22. Where is the pointer?
23. Which cell?
24. Click a cell
25. Paint or erase?
26. Drag to paint
27. Patterns from text
28. The glider gun
29. Fire the gun
30. Buttons on the screen
31. Tap the buttons
32. Build it yourself: a world at rest