Untitled

const finalList = products.reduce((a, c) => {
  const shouldInclude = (inStockOnly ? c.stocked : true) &&
    c.name.toLowerCase().includes(filterText.toLowerCase());
  a.output.push(
    (c.category !== a.lastCategory && <ProductCategoryRow key={c.category} category={c.category} />),
    (shouldInclude && <ProductRow key={c.name} product={c} />));
  a.lastCategory = c.category;
  return a;
}, { lastCategory: null, output: [] });