function validateInputTypes (moveOneType, moveTwoType, moveThreeType) {
  var moveTypesAllowed = ['rock', 'paper', 'scissors'];
  var moveTypes = [moveOneType, moveTwoType, moveThreeType];
  for (i = 0; i < 3; i++) {
    console.log(moveTypesAllowed[i]);
    if (moveTypes.includes(moveTypesAllowed[i]) !== true) {
      console.log('moveType input(s) are invalid.');
      break;
    }
    else if ((moveTypes.includes(moveTypesAllowed[i]) === true) && i === 3){
      console.log('moveType inputs have been validated.');
    }
  }
}

validateInputTypes('rock', 'paper', 'scissors');