I tried to add a button to my code, To change some properties of an array by clicking on it. To do this, I used Context and Reducer. But there is a problem! When I comment the dispatch, the problem is solved and the function is rendered only once. but when I use Reducer, the function rendered infinite times! please help me :( It is worth mentioning that this reducer has been used in other components, but this problem has not occurred.
App.js : (only reducer)
const [goodsState, goodsDispatch] = useReducer(GoodsReducer, {
goods: [
{name : 'x', price : 126000, selected : false, key : 1},
{name : 'y', price : 123000, selected : false, key : 2},
{name : 'z', price : 126000, selected : false, key : 3},
]
});
Cart.js :
import React, { useContext } from "react";
import GoodsContext from "../Contexts/GoodsContext";
export default function Cart(){
const goodsContext = useContext(GoodsContext);
const selectItem = (key) => {
goodsContext.goodsDispatch({ type: "buy-item", payload: { key: key } });
};
return (
<div>
<h1>{selected[0].name}</h1>
<h1>{selected[0].price}</h1>
<button onClick={selectItem(selected[0].key)}>+</button>
//some cod
</div>
);
};
GoodsReducer.js :
export default function GoodsReducer(state, action) {
switch (action.type) {
case "buy-item":
return buyItem(state, action);
default:
return state;
}
}
const buyItem = (state, action) => {
let key = action.payload.key;
changedGoods.selected = true;
const otherGoods = state.goods.filter((good) => good.key !== key);
return {
...state,
goods: [...otherGoods, changedGoods]
};
};
You have to add a Callback to your onClick:
onClick={() => selectItem(selected[0].key)}
Otherwise the selectItem will be called on every render, resulting in an infinte loop of renders. It has nothing to do with useReducer.