Count the Draws

React draws a component by calling its function. When a state changes, React draws that component again, and every component inside it. A console.log in a component makes each draw visible: one line per draw, so you can count them.

memo wraps a component so React skips its draw when every prop is the same as last time. Watch out for functions: a function written inside App is a new function on every draw of App, so a card that gets it as a prop always looks changed. useCallback with an empty dependency array [] hands back the same function on every draw.

A color picker could do it like this:

const Swatch = memo(function Swatch({ color, onPick }) {
  console.log("draw " + color);
  return <button onClick={() => onPick(color)}>{color}</button>;
});

// inside the page component:
const pick = useCallback((color) => setPicked(color), []);

The check opens the page, types p in Search, adds the Pen and clears the search. It must print:

> open the page
  console.log: draw Mug
  …  (one line for each of the 8 products)
  console.log: draw Gift card
> type "p" into "Search"
  (no draw lines: Mug, Notebook and Gift card leave the list)
> click "Add to cart" in "Pen"
    -   text: Cart (0)
    +   text: Cart (1)
> type "" into "Search"
  console.log: draw Mug
  console.log: draw Notebook
  console.log: draw Gift card

Only the three cards that come back are drawn; the five that stayed are left alone.

Your task: in src/App.jsx, write ProductCard wrapped in memo, with a draw log and its li; make addToCart a useCallback with an empty dependency array; and draw one ProductCard for each shown product.

Assignment
Follow the Coding Tutorial to write a memo card that logs its draws, a stable addToCart, and the list that uses them.

Hint
If the five cards with a p still log a draw when you type, onAdd is still a new function each time: check the [] in useCallback.