So I'm learning react at the moment and I've been struggling with this issue.. I'm trying to do tic-tac-toe so I've got this code:
import './App.css';
import { useState } from "react"
const X = 1;
const O = -1;
const EMPTY = 0;
var Square = ({idx, click}) =>
{
let [val, setVal] = useState(EMPTY);
return (
<button onClick={() => {click(setVal, idx);}}>{val}</button>
)
}
var Logger = ({state}) =>
{
return (
<button onClick={() => {console.log(state);}}>log</button>
)
}
var App = () =>
{
let [turn, setTurn] = useState(X);
let state = new Array(9).fill(EMPTY);
let squares = new Array(9);
let click = (setValFunc, idx) =>
{
setTurn(-turn);
setValFunc(turn);
state[idx] = turn;
}
for (let i = 0 ; i < 9 ; i++)
{
squares[i] = (<Square click={click} idx={i}/>);
}
return (
<>
<Logger state={state} />
<div>
{squares}
</div>
</>
)
}
export default App;
so the squares ARE changing as I click them, but when I click the log button to log the state array to the console, the state array remains all zeros.
what am I missing here?
Your state has to be a React state
again. Otherwise, the state you defined inside the App
as a local variable only lasts until the next rerender.
useState
hooklet [state, setState] = useState(new Array(9).fill(EMPTY));
let click = (setValFunc, idx) => {
setTurn(-turn);
setValFunc(turn);
setState((prevState) =>
prevState.map((item, index) => (index === idx ? turn : item))
);
};