const pipeline = async (visitor) => {
  const lead = await captureEmail(visitor);
  const qualified = await nurture(lead);
  const customer = await presentOffer(qualified);
  return customer.revenue;
};

function buildLandingPage(product) {
  return {
    headline: solveMainProblem(product),
    subhead: agitate(product.audience),
    cta: irresistibleOffer(product),
    proof: gatherTestimonials(),
  };
}

// deploy && measure && iterate
const results = await abTest(pageA, pageB);
const winner = results.conversionRate > 0.03
  ? results.variant
  : optimize(results);