Workshop › Rhythm Lanes › Step 29 of 35

Accuracy

What we are doing

How well did you play? A perfect counts fully, a good half, a miss nothing, divided by the number of notes judged: a percentage.

```js
const accuracy = () => {
  const total = judged.perfect + judged.good + judged.miss
  return total === 0 ? 100 : Math.round((100 * (judged.perfect + judged.good * 0.5)) / total)
}
```

What it means

• An arrow function can have a body in braces; then return gives the result.
• total is the number of notes judged so far. With none, the accuracy is 100.
• A good is worth half (* 0.5); Math.round rounds to the nearest whole number.

Your turn

Write accuracy above function update() {, with an empty line after it.

Skills: Functions

← Stop the clock The grade →

All steps

1. A stage for the notes
2. The first lane
3. Four lanes with a loop
4. The hit line
5. A function that draws
6. The song as text
7. From text to notes
8. The clock decides where
9. Draw the notes
10. A clock that ticks
11. The game loop
12. Lanes that light up
13. Keys for the lanes
14. Show the keys
15. Hit the closest note
16. Close enough in time
17. One press, one hit
18. A message on the screen
19. Say Hit
20. Let the message go
21. Perfect or good
22. Keep count
23. Missed notes
24. Score
25. Hits in a row
26. The multiplier
27. The song ends
28. Stop the clock
29. Accuracy
30. The grade
31. The results
32. Play again
33. Best score
34. Lanes you can tap
35. Build it yourself: a speed setting