I'm new to reactjs and and trying to make this simple stopwatch. this code is work in my browser, however when I minimize the browser the time paused, and only continue when I open the browser, do you found something I must be missed? Thanks in advance!
import { useState, useEffect } from "react";
export const SW = () => {
const [mSec, setMSec] = useState(0);
const [sec, setSec] = useState(0);
const [min, setMin] = useState(0);
const [isOn, setIsOn] = useState(false);
const start = () => setIsOn(true);
const stop = () => setIsOn(false);
const reset = () => {
setIsOn(false);
setMin(0);
setSec(0);
setMSec(0);
};
useEffect(() => {
let ms;
if (isOn) {
ms = setInterval(() => setMSec((mSec) => mSec + 1), 10);
if (sec === 59) {
setSec(0);
setMin((min) => min + 1);
}
if (mSec === 99) {
setMSec(0);
setSec((sec) => sec + 1);
}
}
return () => {
clearInterval(ms);
};
}, [mSec, sec, isOn]);
return (
<div>
<p>
{min.toString().padStart(2, "0")}:{sec.toString().padStart(2, "0")}:
{mSec.toString().padStart(2, "0")}
</p>
{!isOn && <button onClick={start}>{!mSec ? "start" : "resume"}</button>}
{isOn && <button onClick={stop}>stop</button>}
<button disabled={!mSec} onClick={reset}>
reset
</button>
</div>
);
};
It's not an issue on useEffect or your code, simply it's how browsers work, they execute JavaScript on the active tabs.
The solution is to use Web Workers API to execute JavaScript in the background.
For more details:
https://developer.mozilla.org/en-US/docs/Web/API/Web_Workers_API/Using_web_workers
https://www.w3schools.com/html/html5_webworkers.asp
Related
I'm new to React and trying to add some audio to a tenzies game.
The audio is getting weirder every time I click the roll button. And after clicking for a while, the sound is fading away. There is also a warning in the console: 'The AudioContext was not allowed to start.'
I can't find out what causing this issue. Please help!
I don't know how to run react code in StackOverflow. So I'm adding a link to the github repository and live site URL of this game.
Here is the full App.js component's code:
import React from 'react';
import Die from './Components/Die';
import { nanoid } from 'nanoid';
import Confetti from 'react-confetti';
import {Howl} from 'howler';
import winSound from './audio/win.mp3';
import rollSound from './audio/roll.mp3';
import holdSound from './audio/hold.mp3';
export default function App(){
const [dice, setDice] = React.useState(generateNewDice());
const [tenzies, setTenzies] = React.useState(false);
const [audio, setAudio] = React.useState(true);
const [rollCount, setRollCount] = React.useState(0);
const [timer, setTimer] = React.useState(0);
const [timerRunning, setTimerRunning] = React.useState(false);
function holdDieObject(){
return {
value: Math.floor(Math.random()*6) + 1,
isHeld: false,
id: nanoid()
}
}
function generateNewDice(){
let newDice= [];
for(let i=0; i<10; i++){
newDice.push(holdDieObject());
}
return newDice;
}
React.useEffect(()=>{ //Count time per 10 milliseconds when timer is running
let interval;
if(timerRunning){
interval = setInterval(() => {
setTimer((prevTime) => prevTime + 10)
}, 10)
}else{
clearInterval(interval);
}
return () => clearInterval(interval);
},[timerRunning])
React.useEffect(()=>{ //Check all the dice are matched or not
const someDiceHeld = dice.some(die => die.isHeld);
const allDiceHeld = dice.every(die => die.isHeld);
const firstDiceValue = dice[0].value;
const allSameValue = dice.every(die=> die.value === firstDiceValue);
if(someDiceHeld){
setTimerRunning(true);
}
if(allDiceHeld && allSameValue){
setTenzies(true);
// audio && victorySound.play(); // This brings up dependency warning. So moved it to the bottom
setTimerRunning(false)
}
},[dice])
const victorySound = new Howl({
src: [winSound]
})
if(tenzies){
audio && victorySound.play(); // Here
}
const rollDieSound = new Howl({
src: [rollSound]
})
const holdDieSound = new Howl({
src: [holdSound]
})
function holdDice(id){
audio && holdDieSound.play();
setDice(oldDice => oldDice.map(die =>{
return die.id===id ?
{
...die,
isHeld: !die.isHeld
} :
die;
}))
}
function rollDice(){
if(!tenzies){
setDice(oldDice => oldDice.map(die=>{
audio && rollDieSound.play();
return die.isHeld ? die : holdDieObject();
}))
setRollCount(prevCount => prevCount + 1);
}else{
setTenzies(false);
setDice(generateNewDice());
setRollCount(0);
setTimer(0);
}
}
function toggleMute(){
setAudio(prevState => !prevState);
}
function startNewGame(){
setTenzies(false);
setDice(generateNewDice());
}
const minutes = <span>{("0" + Math.floor((timer / 60000) % 60)).slice(-2)}</span>
const seconds = <span>{("0" + Math.floor((timer / 1000) % 60)).slice(-2)}</span>
const milliseconds = <span>{("0" + ((timer / 10) % 100)).slice(-2)}</span>
const dieElements = dice.map((die) => {
return <Die key={die.id}
value={die.value}
isHeld={die.isHeld}
holdDice={()=> holdDice(die.id)}
/>
})
return(
<div>
<main className="board">
<button onClick={toggleMute} className="mute-btn">{audio ? "🔉" : "🔇"}</button>
<h1>Tenzies</h1>
<p>Roll untill the dice are the same. Click each die to freeze it at its current value between rolls.</p>
<div className="die-container">
{dieElements}
</div>
<button onClick={rollDice}>Roll</button>
{tenzies && <div className="scoreboard">
<h2>Congratulations!</h2>
<p className='rollCount'>Rolled: {rollCount}</p>
<p className="rolltime">Time Taken: {minutes}:{seconds}:{milliseconds}</p>
<h3>Your Score: 4500</h3>
<button className='close' onClick={startNewGame}>New Game</button>
</div>}
</main>
{tenzies && <Confetti className="confetti" recycle={false} />}
</div>
)
}
Why is the min state getting updated in the multiples of two instead of just updating by one after every 59 seconds? How do I fix it?
import { useRef, useState } from "react";
export const Timer = () => {
const [second, setSecond] = useState(0);
const [min, setMin] = useState(0);
const watch = useRef(null);
const startTimer = () => {
watch.current = setInterval(() => {
setSecond((value) => {
if (value === 59) {
setSecond(0);
setMin((v) => v + 1);
}
return value + 1;
});
}, 1000);
};
return (
<div>
<h1>
{min}:{second}{" "}
</h1>
<button onClick={startTimer}>Start</button>
<button onClick={() => clearInterval(watch.current)}>Pause</button>
<button
onClick={() => {
setSecond(0);
return clearInterval(watch.current);
}}
>
Reset
</button>
</div>
);
};
This is the component as a whole. I am new to react so please help.
I am trying to create a Pomodoro timer in ReactJS. I am having trouble having the timer to stop it's countdown.
PomView.js
const PomView = () => {
const [timer, setTimer] = useState(1500) // 25 minutes
const [start, setStart] = useState(false)
var firstStart = useRef(true)
var tick;
useEffect( () => {
if (firstStart.current) {
console.log("first render, don't run useEffect for timer")
firstStart.current = !firstStart.current
return
}
console.log("subsequent renders")
console.log(start)
if (start) {
tick = setInterval(() => {
setTimer(timer => {
timer = timer - 1
console.log(timer)
return timer
}
)
}, 1000)
} else {
console.log("clear interval")
clearInterval(tick);
}
}, [start])
const toggleStart = () => {
setStart(!start)
}
const dispSecondsAsMins = (seconds) => {
// 25:00
console.log("seconds " + seconds)
const mins = Math.floor(seconds / 60)
const seconds_ = seconds % 60
return mins.toString() + ":" + ((seconds_ == 0) ? "00" : seconds_.toString())
}
return (
<div className="pomView">
<ul>
<button className="pomBut">Pomodoro</button>
<button className="pomBut">Short Break</button>
<button className="pomBut">Long Break</button>
</ul>
<h1>{dispSecondsAsMins(timer)}</h1>
<div className="startDiv">
{/* event handler onClick is function not function call */}
<button className="startBut" onClick={toggleStart}>{!start ? "START" : "STOP"}</button>
{start && <AiFillFastForward className="ff" onClick="" />}
</div>
</div>
)
}
export default PomView
Although the clearInterval runs in the else portion of useEffect, the timer continues ticking. I am not sure if it is because of the asynchronous setTimer method in useEffect. I would like to know what the problem is with the code I have written.
You store the timer ref in tick, but each time the component rerenders the tick value from the previous render is lost. You should also store tick as a React ref.
You are also mutating the timer state.
setTimer((timer) => {
timer = timer - 1; // mutation
return timer;
});
Just return the current value minus 1: setTimer((timer) => timer - 1);
Code
const PomView = () => {
const [timer, setTimer] = useState(1500); // 25 minutes
const [start, setStart] = useState(false);
const firstStart = useRef(true);
const tick = useRef(); // <-- React ref
useEffect(() => {
if (firstStart.current) {
firstStart.current = !firstStart.current;
return;
}
if (start) {
tick.current = setInterval(() => { // <-- set tick ref current value
setTimer((timer) => timer - 1);
}, 1000);
} else {
clearInterval(tick.current); // <-- access tick ref current value
}
return () => clearInterval(tick.current); // <-- clear on unmount!
}, [start]);
...
};
useEffect( () => {
const tick= setInterval(fun, 1000);
return ()=>{
clearInterval(tick);
}
}, [])
useEffect has it's own release way.
How can I stop the both the timer when my button is clicked in reactjs.
I have noticed that when my timer is running my whole component is re-rendering every-time how to avoid this part.
export default function App() {
const [counterSecond, setCounterSecond] = React.useState(0);
const [counter, setCounter] = React.useState(120);
const [time, setTime] = React.useState("");
React.useEffect(() => {
setTimeout(() => setCounterSecond(counterSecond + 1), 1000);
setTimeout(() => setCounter(counter - 1), 1000);
}, [counterSecond , counter]);
const handletimer = () => {
setTime(counterSecond);
};
return (
<div className="App">
<div>Countdown: {counterSecond}</div>
<div>Countdown Reverse: {counter}</div>
<div>time: {time} </div>
<button onClick={handletimer}>Submit</button>
</div>
);
}
The best way is to add a state variable representing the status of work. ie: 'working', 'paused' and toggle it.
Also, you need to unsubscribe from timeout to avoid state updates if the component get unmounted.
here is an example where you can stop and resume the timers:
export default function App() {
const [counterSecond, setCounterSecond] = React.useState(0);
const [counter, setCounter] = React.useState(120);
const [time, setTime] = React.useState("");
const [status, setStatus] = React.useState("working");
React.useEffect(() => {
let secondCounterId;
let counterId;
if (status === "working") {
secondCounterId = setTimeout(
() => setCounterSecond(counterSecond + 1),
1000
);
counterId = setTimeout(() => setCounter(counter - 1), 1000);
}
return () => {
clearTimeout(counterId);
clearTimeout(secondCounterId);
};
}, [counterSecond, counter, status]);
const handletimer = () => {
setTime(counterSecond);
};
const stopTimers = () => {
setStatus("paused");
};
const resume = () => {
setStatus("working");
};
return (
<div className="App">
<div>Countdown: {counterSecond}</div>
<div>Countdown Reverse: {counter}</div>
<div>time: {time} </div>
<button onClick={handletimer}>Submit</button>
<button onClick={stopTimers}>Stop</button>
<button onClick={resume}>resume</button>
</div>
);
}
And a working codesandbox
You can create a timerRunning (boolean) variable to check if the timer should run in the useEffect() like this:
const [timerRunning, setTimerRunning] = React.useState(true);
React.useEffect(() => {
if (timerRunning) {
setTimeout(() => setCounterSecond(counterSecond + 1), 1000);
setTimeout(() => setCounter(counter - 1), 1000);
}
}, [counterSecond , counter, timerRunning]);
Then toggle the timerRunning in the handletimer:
const handletimer = () => {
setTimerRunning(false);
// ... other logic
};
The reason time is running because after each render useEffect() will be called.Hence the time. So to correct it, you can set like if "time" is in initialstate then do those functionality otherwise not. So after rendering time will be set set to new time and problem will be solved.
I'm trying to refactor my code to react hooks, but I'm not sure if i'm doing it correctly. I tried copying and pasting my setInterval/setTimout code into hooks, but it did not work as intended. After trying different things I was able to get it to work, but I'm not sure if this is the best way to do it.
I know i can use useEffect to clear interval on un-mount, but I want to clear it before un-mounting.
Is the following good practice and if not what is a better way of clearing setInterval/setTimout before un-mounting?
Thanks,
useTimeout
import { useState, useEffect } from 'react';
let timer = null;
const useTimeout = () => {
const [count, setCount] = useState(0);
const [timerOn, setTimerOn] = useState(false);
useEffect(() => {
if (timerOn) {
console.log("timerOn ", timerOn);
timer = setInterval(() => {
setCount((prev) => prev + 1)
}, 1000);
} else {
console.log("timerOn ", timerOn);
clearInterval(timer);
setCount(0);
}
return () => {
clearInterval(timer);
}
}, [timerOn])
return [count, setCount, setTimerOn];
}
export default useTimeout;
Component
import React from 'react';
import useTimeout from './useTimeout';
const UseStateExample = () => {
const [count, setCount, setTimerOn] = useTimeout()
return (
<div>
<h2>Notes:</h2>
<p>New function are created on each render</p>
<br />
<h2>count = {count}</h2>
<button onClick={() => setCount(prev => prev + 1)}>Increment</button>
<br />
<button onClick={() => setCount(prev => prev - 1)}>Decrement</button>
<br />
<button onClick={() => setTimerOn(true)}>Set Interval</button>
<br />
<button onClick={() => setTimerOn(false)}>Stop Interval</button>
<br />
</div>
);
}
export default UseStateExample;
--- added # 2019-02-11 15:58 ---
A good pattern to use setInterval with Hooks API:
https://overreacted.io/making-setinterval-declarative-with-react-hooks/
--- origin answer ---
Some issues:
Do not use non-constant variables in the global scope of any modules. If you use two instances of this module in one page, they’ll share those global variables.
There’s no need to clear timer in the “else” branch because if the timerOn change from true to false, the return function will be executed.
A better way in my thoughts:
import { useState, useEffect } from 'react';
export default (handler, interval) => {
const [intervalId, setIntervalId] = useState();
useEffect(() => {
const id = setInterval(handler, interval);
setIntervalId(id);
return () => clearInterval(id);
}, []);
return () => clearInterval(intervalId);
};
Running example here:
https://codesandbox.io/embed/52o442wq8l?codemirror=1
In this example, we add a couple of things...
A on/off switch for the timeout (the 'running' arg) which will completely switch it on or off
A reset function, allowing us to set the timeout back to 0 at any time:
If called while it's running, it'll keep running but return to 0.
If called while it's not running, it'll start it.
const useTimeout = (callback, delay, running = true) => {
// save id in a ref so we make sure we're always clearing the latest timeout
const timeoutId = useRef('');
// save callback as a ref so we can update the timeout callback without resetting it
const savedCallback = useRef();
useEffect(
() => {
savedCallback.current = callback;
},
[callback],
);
// clear the timeout and start a new one, updating the timeoutId ref
const reset = useCallback(
() => {
clearTimeout(timeoutId.current);
const id = setTimeout(savedCallback.current, delay);
timeoutId.current = id;
},
[delay],
);
// keep the timeout dynamic by resetting it whenever its' deps change
useEffect(
() => {
if (running && delay !== null) {
reset();
return () => clearTimeout(timeoutId.current);
}
},
[delay, running, reset],
);
return { reset };
};
So in your example above, we could use it like so...
const UseStateExample = ({delay}) => {
// count logic
const initCount = 0
const [count, setCount] = useState(initCount)
const incrementCount = () => setCount(prev => prev + 1)
const decrementCount = () => setCount(prev => prev - 1)
const resetCount = () => setCount(initCount)
// timer logic
const [timerOn, setTimerOn] = useState(false)
const {reset} = useTimeout(incrementCount, delay, timerOn)
const startTimer = () => setTimerOn(true)
const stopTimer = () => setTimerOn(false)
return (
<div>
<h2>Notes:</h2>
<p>New function are created on each render</p>
<br />
<h2>count = {count}</h2>
<button onClick={incrementCount}>Increment</button>
<br />
<button onClick={decrementCount}>Decrement</button>
<br />
<button onClick={startTimer}>Set Interval</button>
<br />
<button onClick={stopTimer}>Stop Interval</button>
<br />
<button onClick={reset}>Start Interval Again</button>
<br />
</div>
);
}
Demo of clear many timers.
You should declare and clear timer.current instead of timer.
Declare s and timer.
const [s, setS] = useState(0);
let timer = useRef<NodeJS.Timer>();
Initialize timer in useEffect(() => {}).
useEffect(() => {
if (s == props.time) {
clearInterval(timer.current);
}
return () => {};
}, [s]);
Clear timer.
useEffect(() => {
if (s == props.time) {
clearInterval(timer.current);
}
return () => {};
}, [s]);
After many attempts to make a timer work with setInterval, I decided to use setTimeOut, I hope it works for you.
const [count, setCount] = useState(60);
useEffect(() => {
if (count > 0) {
setTimeout(() => {
setCount(count - 1);
}, 1000);
}
}, [count]);