Question 197823 in Javascript Question posted in
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Javascript – stopping counter at 0

I have two functions that increment and decrement number of items by 1, but when I decrement I want to stop at 0? this are the functions

const addToCart = (productId) => {
    setCartItems((prev) => ({
      ...prev,
      [productId]: prev[productId] + 1,
    }));
  };

  const removeToCart = (productId) => {
    setCartItems((prev) => ({
      ...prev,
      [productId]: prev[productId] - 1,
    }));
  };

they are then called in button by onClick action

<button
              className="add-btn mx-2"
              onClick={() => {
                addToCart(product.id);
              }}
            >
              {" "}
              +
</button>
<button
              className="add-btn mx-2"
              onClick={() => {
                removeToCart(product.id);
              }}
            >
              {" "}
              -
</button>
Tags:

2

Answers


  1. 0

    You can use Math.max to cap the value.

    const removeToCart = (productId) => {
    setCartItems((prev) => ({
      ...prev,
      [productId]: Math.max(prev[productId] - 1, 0),
    }));
};
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  2. 0

    Why not just modify removeToCart to look at the value of prev[productId] and if it is less than or equal to 0, then do nothing otherwise do the decrement?

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