Rock paper scissor project

I just need help with my project… Im trying my best to find my error and to finish but the last part or user paper computer scissors or rock is making an error. If anyone can help it would be greatly appreciated
onst getUserChoice = userInput => {
userInput = userInput.toLowerCase();
if (userInput === ‘rock’ || userInput === ‘paper’ || userInput === ‘scissors’ ) {
return userInput
} else {
console.log(‘Error! Please type rock, paper or scissors. Thank you’)
}

}
const getComputerChoice = () => {
const rand = Math.floor(Math.random() * 3);
switch (rand) {
case 0:
return ‘rock’;
case 1:
return ‘paper’;
case 2:
return ‘scissors’
};
}

const determineWinner = (userChoice, computerChoice) => {
if (userChoice === computerChoice) {
return ‘Game is a tie!’;
}
if (userChoice === ‘rock’) {
if (computerChoice === ‘paper’) {
return ‘Sorry the computer has won’;
} else {
return ‘Congratulations you have won!’;
}
}
if (userChoice === ‘paper’){
if (computerChoice === ‘scissors’ || computerChoice === ‘rock’){
return ‘Sorry the computer has won!’;
} else {
return ‘Congratulatinons you have won!’;
}
}
};

If userChoice is "paper" and computerChoice is "scissors", then the computer wins,
but if userChoice is "paper" and computerChoice is "rock", then the user wins.

Therefore,
if (computerChoice === 'scissors' || computerChoice === 'rock'){
should be
if (computerChoice === 'scissors')
so that computerChoice === 'rock' would be dealt with by the else.

Let’s look at this from a probability perspective and count the number of all possible outcomes. For this example, a will be the user, b will be the computer (choice, that is).

a === b => rock
a === b => paper
a === b => scissors

from here on we know they are different.

a === rock b === paper     => b wins
a === rock b === scissors  => a wins

a === paper b === scissors => b wins
a === paper b === rock     => a wins

a === scissors b === rock  => b wins
a === scissors b === paper => a wins

The above suggests three if statements, each with a nested if…else.