Lemon Squeezy を接続し、注文を訪問に紐づける

// On pages with Lemon Squeezy buy links: add the visitor id as custom data.
const visitorId = (document.cookie.match(/(?:^|; )_tally_vid=([\w-]+)/) || [])[1];
for (const link of document.querySelectorAll('a[href*=".lemonsqueezy.com/checkout/buy/"]')) {
  const url = new URL(link.href);
  if (visitorId && !url.searchParams.has('checkout[custom][tally_visitor_id]')) {
    url.searchParams.set('checkout[custom][tally_visitor_id]', visitorId);
    link.href = url.href;
  }
}

// Express with cookie-parser, where you create a Lemon Squeezy checkout.
app.post('/checkout', async (req, res) => {
  const visitorId = req.cookies['_tally_vid'];
  const response = await fetch('https://api.lemonsqueezy.com/v1/checkouts', {
    method: 'POST',
    headers: {
      Accept: 'application/vnd.api+json',
      'Content-Type': 'application/vnd.api+json',
      Authorization: 'Bearer ' + process.env.LEMONSQUEEZY_API_KEY,
    },
    body: JSON.stringify({
      data: {
        type: 'checkouts',
        attributes: { checkout_data: { custom: visitorId ? { 'tally_visitor_id': visitorId } : {} } },
        relationships: {
          store: { data: { type: 'stores', id: '1' } },
          variant: { data: { type: 'variants', id: '1' } },
        },
      },
    }),
  });
  const { data } = await response.json();
  res.redirect(303, data.attributes.url);
});