const sum = Number(sumDecimal)
  const heads = Math.random() < 0.5
  // if this category is selected, double its proportion
  // if it isn't select, zero its proportion
  const itemRewardMult = heads ? 0 : 2.0
  const upvoteRewardMult = heads ? 2.0 : 0

// untested code
{
   item.ncomments < 3 ? 'early comments get more zaps' :
   item.ncomments < 6 ? 'comments are heating up, don't stay out in cold' :
   item.ncomments < 9 ? 'comments are hot, don't burn yourself' :
   item.ncomments < 12 ? 'it's likely that someone has already thought the same as you, consider reading the comments before writing your own' :
   item.ncomments < 15 ? 'list of comments is already long, add one more' : 'fractions of a penny for your thoughts?')
}