See https://github.com/dddddddddzzzz/OpenHeart

worker.js

addEventListener('fetch', event => {
  event.respondWith(handleRequest(event.request))
})

async function handleRequest(request) {
  if (request.method !== 'POST') return

  const url = new URL(request.url)
  const id = url.searchParams.get('id')
  const emoji = ensureEmoji(await request.text())

  if (!id || !emoji) return new Response('not ok', {status: 500})

  const key = `${id}:${emoji}`

  // https://developers.cloudflare.com/workers/runtime-apis/kv/
  const currentCount = Number(await(NAMESPACE.get(key)) || 0)
  await NAMESPACE.put(key, currentCount + 1)

  return new Response('ok')
}

function ensureEmoji(emoji) {
  const segments = Array.from(new Intl.Segmenter({ granularity: 'grapheme' }).segment(emoji.trim()))
  const parsedEmoji = segments.length > 0 ? segments[0].segment : null
  
  if (/\p{Emoji}/u.test(parsedEmoji)) return parsedEmoji
}

Hi! I updated this here to enable the same Cloudflare worker to also respond to the GET requests that openHeart.getCount() sends out. Sorry if it's terrible, it's literally the first thing I've ever written in JS. Also I updated it to ES modules format, because apparently what's what Cloudflare prefers now.