const cart = [{ name: "Блокнот", price: 220 }];

const cart = [];
function render() {
  document.querySelector("#count").textContent = cart.length;
  document.querySelector("#sum").textContent = cart.reduce((s, d) => s + d.price, 0);
}

const cart = [{ name: "Блокнот", price: 220 }, { name: "Пенал", price: 290 }];
function render() {
  document.querySelector("#count").textContent = cart.length;
  document.querySelector("#sum").textContent = cart.reduce((s, d) => s + d.price, 0);
}