JSFiddle - React, Tailwind, and code Playground

JavaScript

var weapons = ['paper', 'scissors', 'rock'],
	user = 'scissors',
	machine = 'paper',
	uIdx = weapons.indexOf(user),
	mIdx = weapons.indexOf(machine),
	winner;
if (uIdx !== mIdx) {
	winner = (mIdx === (uIdx + 1) % 3) ? 'machine' : 'user';
} else {
	winner = 'tie';
}

console.log(winner);