rock paper scissors javascript

1const tolowerUcFirst = v => v.charAt(0).toUpperCase() + v.slice(1).toLowerCase()
2
3const answer = prompt(
4  'Do you want to play Rock Paper Scissors? Type yes or no!'
5)
6
7if (answer && ['Y', 'YES'].includes(answer.toUpperCase())) {
8  let board = ['ROCK', 'PAPER', 'SCISSORS']
9  let answer = prompt('Rock, Paper, or Scissors?')
10
11  if (board.includes(answer.toUpperCase())) {
12    let them = board[Math.floor(Math.random() * 3)]
13    let you = answer.toUpperCase()
14
15    if (them === you) {
16      console.log('draw', you, them)
17      alert(`Draw, they choose ${tolowerUcFirst(them)} too!`)
18    } else {
19      // win rules
20      if (
21        // SCISSORS
22        (you === 'SCISSORS' && them === 'PAPER') ||
23        // PAPER
24        (you === 'PAPER' && them === 'ROCK') ||
25        // ROCK
26        (you === 'ROCK' && them === 'SCISSORS')
27      ) {
28        console.log('you win', you, them)
29        alert(`You win, they choose ${tolowerUcFirst(them)}!`)
30      } else {
31        console.log('you lose', you, them)
32        alert(`You lose, they choose ${tolowerUcFirst(them)}!`)
33      }
34    }
35  }
36}