Calling react hook from a function on another page - reactjs

Question

I am making a chess game and I need to integrate a count down timer, e.g - so when it's the white players turn their clock is counting down until they move.
To avoid changing a lot more code that is not present in this question ,I would like to keep function "move" as is, though I could change CountDownTimer if needed,
For now I would like to know how to call the react hook setTimerOn in the CountDownTimer component from the function move,then I can work out the rest myself.
From what I have read you cannot do this with react hooks? so just looking for
anything that works, if that means changing CountDownTimer.
export function move(from, to, promotion) {
let tempMove = { from, to }
if (member.piece === chess.turn()) {
const legalMove = chess.move(tempMove)
if (legalMove) {
updateGame()
//i would like to access CountDownTimer and call setTimerOn(true)
// i can work out the code for white and black / start and stop myself afterwards
}
}
,
}
import React from 'react'
function CountDownTimer(){
const [time, setTime] = React.useState(0);
const [timerOn, setTimerOn] = React.useState(false);
React.useEffect(() => {
let interval = null;
if (timerOn) {
interval = setInterval(() => {
setTime((prevTime) => prevTime + 10);
}, 10);
} else if (!timerOn) {
clearInterval(interval);
}
return () => clearInterval(interval);
}, [timerOn]);
return (
<div className="Timers">
<h2>Stopwatch</h2>
<div id="display">
<span>{("0" + Math.floor((time / 60000) % 60)).slice(-2)}:</span>
<span>{("0" + Math.floor((time / 1000) % 60)).slice(-2)}:</span>
<span>{("0" + ((time / 10) % 100)).slice(-2)}</span>
</div>
<div id="buttons">
{!timerOn && time === 0 && (
<button onClick={() => setTimerOn(true)}>Start</button>
)}
{timerOn && <button onClick={() => setTimerOn(false)}>Stop</button>}
{!timerOn && time > 0 && (
<button onClick={() => setTime(0)}>Reset</button>
)}
{!timerOn && time > 0 && (
<button onClick={() => setTimerOn(true)}>Resume</button>
)}
</div>
</div>
);
});
export default CountDownTimer; ```

Answer 1

Based on React documentation, React Hook can be called from function components or other hooks.
In your situation, you should consider the utilization of React Context. You need to move up timerOn state and setTimerOn method as context values. So that, all components which are wrapped by the context provider can utilize the values.
First, create some helpers for managing context.
// TimerOn.js
import React, { createContext, useContext } from 'react';
// create a context
const TimerOnContext = createContext();
// create a hook to provide context value
export function useTimerOn() {
const contextValue = useContext(TimerOnContext);
return contextValue;
}
// custom provider that will wrap your main components
export function TimerOnProvider({ children }) {
const [timerOn, setTimerOn] = React.useState(false);
return (
<TimerOnContext.Provider value={{ timerOn, setTimerOn }}>
{children}
</TimerOnContext.Provider>
);
}
For instance, I create two simple components to demonstrate the timer component and caller component.
// CountDownTimer.js
import React from "react";
import { useTimerOn } from "./TimerOn";
export default function CountDownTimer() {
const { timerOn } = useTimerOn();
// detect changes
React.useEffect(() => {
if (timerOn) {
console.log('timer is on');
} else {
console.log('timer is off');
}
}, [timerOn]);
return (
<div>{timerOn ? 'timer on' : 'timer off'}</div>
);
}
// MoveCaller.js
import React from "react";
import { useTimerOn } from "./TimerOn";
export default function MoveCaller() {
const { timerOn, setTimerOn } = useTimerOn();
// move then set timer
const move = () => {
setTimerOn(!timerOn);
}
return (
<div>
<button type="button" onClick={move}>
Move
</button>
</div>
);
}
Then, you can wrap all main components with the provider component. So, the move function in a component can change the state of timerOn and be read by another component.
import React from 'react';
import CountDownTimer from './CountDownTimer';
import MoveCaller from './MoveCaller';
import { TimerOnProvider } from './TimerOn';
export default function ChessApp() {
return (
<TimerOnProvider>
<CountDownTimer />
<MoveCaller />
</TimerOnProvider>
);
}