React 和道具深度的问题

Question

I don't know why this is happening. When I try to setArray to a data.map, React complains and I have no idea why. Here are the codes of key components. I've also tried to move the useState hook into the 's parent element and passing it as props but I got the same error

My Data Component:

export let DataContext = createContext();

export let DataProvider = (props) => {
  let [array, setArray] = useState([]);
  let [data, setData] = useState([
    {
      name: "Toshiba",
      desc: "Laptop copmuter",
      price: 299,
      url:
        "https://images.pexels.com/photos/3975677/pexels-photo-3975677.jpeg?auto=compress&cs=tinysrgb&dpr=2&h=650&w=940",
      path: "Toshiba",
      type: "laptop",
      details:
        "Some words just to fill this space Some words just to fill this space Some words just to fill this space Some words just to fill this space Some words just to fill this space Some words just to fill this space Some words just to fill this space Some words just to fill this space",
    },
    {
      name: "Lenovo",
      desc: "Laptop copmuter",
      price: 399,
      url:
        "https://images.pexels.com/photos/3975677/pexels-photo-3975677.jpeg?auto=compress&cs=tinysrgb&dpr=2&h=650&w=940",
      path: "Lenovo",
      type: "laptop",
      details:
        "Some words just to fill this space Some words just to fill this space Some words just to fill this space Some words just to fill this spaceSome words just to fill this space Some words just to fill this space Some words just to fill this space Some words just to fill this space",
    },
    {
      name: "Asus",
      desc: "Laptop copmuter",
      price: 199,
      url:
        "https://images.pexels.com/photos/3975677/pexels-photo-3975677.jpeg?auto=compress&cs=tinysrgb&dpr=2&h=650&w=940",
      path: "Asus",
      type: "laptop",
      details:
        "Some words just to fill this space Some words just to fill this space Some words just to fill this space Some words just to fill this space Some words just to fill this space Some words just to fill this space Some words just to fill this space Some words just to fill this space",
    },
    {
      name: "HP",
      desc: "Laptop copmuter",
      price: 299,
      type: "laptop",
      url:
        "https://images.pexels.com/photos/3975677/pexels-photo-3975677.jpeg?auto=compress&cs=tinysrgb&dpr=2&h=650&w=940",
      path: "HP",
      details:
        "Some words just to fill this space Some words just to fill this space Some words just to fill this space Some words just to fill this space Some words just to fill this space Some words just to fill this space  Some words just to fill this space Some words just to fill this space Some words just to fill this space Some words just to fill this space ",
    },
    {
      name: "Apple",
      desc: "Laptop copmuter",
      price: 299,
      type: "laptop",
      url:
        "https://images.pexels.com/photos/3975677/pexels-photo-3975677.jpeg?auto=compress&cs=tinysrgb&dpr=2&h=650&w=940",
      path: "Apple",
      details:
        "Some words just to fill this space Some words just to fill this space Some words just to fill this space Some words just to fill this spaceSome words just to fill this space Some words just to fill this space Some words just to fill this space Some words just to fill this space",
    },
    {
      name: "Apple",
      desc: "Android",
      price: 299,
      type: "mobile",
      url:
        "https://images.pexels.com/photos/3975677/pexels-photo-3975677.jpeg?auto=compress&cs=tinysrgb&dpr=2&h=650&w=940",
      path: "Apple",
      details:
        "Some words just to fill this space Some words just to fill this space Some words just to fill this space Some words just to fill this spaceSome words just to fill this space Some words just to fill this space Some words just to fill this space Some words just to fill this space",
    },
  ]);

  return (
    <DataContext.Provider value={[data, setData, array, setArray]}>
      {props.children}
    </DataContext.Provider>
  );

****My Item Component that I get error on: ****

function Item() {
  let [data, setData, array, setArray] = useContext(DataContext);

  let newAr = data.map((item) => {
    return (
      <div className="Item">
        <img src={item.url} />
        <h1>{item.name}</h1>
        <p>{item.desc}</p>
        <h2>{item.price}</h2>
        <Link to={`/product/${item.path}`}>
          <h3>See details</h3>
        </Link>
      </div>
    );
  });

  setArray([newAr]);

  return <>{array}</>;
}

Answer 1

You should not do

  setArray([newAr]);

inside the component as it is. It needs to be done or in event handler, or in useEffect hook.

Right now, you just recursively updating component. Component renders - component updates newAr - it gets signal set newAr is updated - it rerender components - component updates newAr - etc It falls in a never ending loop.

try

  useEffect(() => {
    setArray([newAr]);
  }, []) 

This will update newAr only when component is mounted.

PS It is no a good approach to store React Nodes in the state.