Created a timer, I want to be able to stop the interval once the seconds drop down to 0.
This is what I got so far
useEffect(() => {
if (alarm?.timerOn && alarm?.seconds === 0) {
console.log('stop?')
clearInterval(alarmTimer)
console.log('stop? below clear interval')
}
}, [alarm?.seconds])
The console logs appear exactly at 0 just like I want it but the clear interval doesn't do anything? I have declared the alarmTimer like this let alarmTimer: any outside the useEffect
How the start timer works
alarmTimer = setInterval(() => {
if (alarm!.seconds > 0) {
dispatch!({ type: 'DECREMENT_SECONDS' })
}
}, 1000)
So instead of clearing at 0 it carrys on and goes down to -1,-2,-3 etc
Decided to use Ref instead like this and it seems to have worked!
const intervalRef = useRef(null)
intervalRef.current = setInterval(() => {
if (alarm!.seconds > 0) {
dispatch!({ type: 'DECREMENT_SECONDS' })
}
}, 1000)
useEffect(() => {
if (alarm?.timerOn && alarm?.seconds === 0) {
clearInterval(intervalRef.current)
intervalRef.current = null
}
}, [alarm?.seconds])
Related
I implemented a timer which works fine but the only problem is that it doesn't clearInterval when the timer ends .
My code looks like this :
const [currentCount, setCurrentCount] = React.useState(10);
const [intervalId, setIntervalId] = React.useState(10);
React.useEffect(() => {
const intervalId = setInterval(timer, 1000);
// store intervalId in the state so it can be accessed later:
setIntervalId(intervalId);
return () => {
clearInterval(intervalId);
};
}, []);
const timer = () => {
setCurrentCount((prev) => {
if (prev > 0) {
return prev - 1;
} else if (prev === 0) {
console.log("Still Runs");
clearInterval(intervalId);
return prev;
}
});
};
The value of currentCount decreases from 10 to 0 but I want to clear the interval when it reaches 0 and I tried to clear it with this piece of code clearInterval(intervalId) but didn't work .
How can I clearInterval when the value of currentCount reaches 0 ?
Your useEffect hook is missing an important dependency from its dependency array: timer. To make things simpler on yourself, you can move the timer variable inside the effect (unless you have a good reason for it to be outside). This ends up having the added bonus that the timer function will be able to reference the interval ID without maintaining it in state.
const [currentCount, setCurrentCount] = React.useState(10);
React.useEffect(() => {
const timer = () => {
setCurrentCount((prev) => {
if (prev > 0) {
return prev - 1;
} else if (prev === 0) {
console.log("Still Runs");
clearInterval(intervalId);
return prev;
}
});
};
const intervalId = setInterval(timer, 1000);
return () => {
clearInterval(intervalId);
};
}, []);
I created a timer function it's working but when I click clearInterval it's not working, timer still going on.
Here is my function to start timer. Maximum limit for timer is 60sec
const StartRecord = ()=>{
const timeout = setInterval(() => {
if (time != 60) {
setTime(prevState => prevState + 1);
}
}, 1000);
console.log(timeout);
if (time == 60) {
clearInterval(timeout);
}
}
here is my function to stop timer
const onStopRecord = () => {
clearInterval(time);
}
can anyone tell me why it's not working?
You are trying clearInterval using time. It should be timeout
const onStopRecord = () => {
clearInterval(timeout);
}
you can use useEffect to do this task
useEffect(() => {
let interval
if(time != 60){
interval = setInterval(() => setTime((prev) => prev + 1), 1000);
}
return () => clearInterval(interval);
}, [time])
I need to exit from a running interval if the conditions are correct:
var refreshId = setInterval(function() {
var properID = CheckReload();
if (properID > 0) {
<--- exit from the loop--->
}
}, 10000);
Use clearInterval:
var refreshId = setInterval(function() {
var properID = CheckReload();
if (properID > 0) {
clearInterval(refreshId);
}
}, 10000);
Pass the value of setInterval to clearInterval.
const interval = setInterval(() => {
clearInterval(interval);
}, 1000)
Demo
The timer is decremented every second, until reaching 0.
let secondsRemaining = 10
const interval = setInterval(() => {
// just for presentation
document.querySelector('p').innerHTML = secondsRemaining
// time is up
if (secondsRemaining === 0) {
clearInterval(interval);
}
secondsRemaining--;
}, 1000);
<p></p>
Updated for ES6
You can scope the variable to avoid polluting the namespace:
const CheckReload = (() => {
let counter = - 5;
return () => {
counter++;
return counter;
};
})();
{
const refreshId = setInterval(
() => {
const properID = CheckReload();
console.log(properID);
if (properID > 0) {
clearInterval(refreshId);
}
},
100
);
}
I am practically new to React. In this App I am using Hooks!
I've made a Countdown Timer that will show in a few seconds after logging in. I am unable to make it stop on a button click. I need some advise on this as I've been struggling for the past 2 days with this.
This is my code so far: (Please Help)
function Admin() {
const [isTimerOpen, setTimmer] = useState(false);
let history = useHistory();
// SET BY THE ADMIN
var minutesToCountDown = 0.9;
// TRANSFORM INTO SECONDS
var transformMinutesToSeconds = minutesToCountDown * 60
// KEEP A STATE
const [counterValue, setCounterValue] = useState(0);
const [isTimmerStoped, setStopTimer] = useState(false);
// FUNCTION TO HAPPEN EVERY 1 SECOND
function timeIt() {
if (isTimmerStoped === false) {
transformMinutesToSeconds--
setCounterValue(transformMinutesToSeconds)
console.log("Timer is on: ", transformMinutesToSeconds)
if (transformMinutesToSeconds === 0) {
clearInterval(interval)
setStopTimer(true)
}
} else {
setStopTimer(true)
clearInterval(interval)
}
}
// STARTS THE COUNTDOWN
var interval;
const startCountdown = () => {
interval = setInterval(timeIt, 1000)
}
const stopCountdown = () => {
console.log("Stop Timer")
setStopTimer(true);
setCounterValue(0);
setTimmer(false);
}
// ADD 0 IN FRONT ON THE TIME REMAINING
const addLeadingZeros = value => {
value = String(value);
while (value.length < 2) {
value = `0${value}`;
}
return value;
};
// CONVERT SECONDS INTO TIME REMAINING
function convertSeconds(seconds) {
var min = Math.floor(seconds / 60);
var sec = seconds % 60;
return addLeadingZeros(min) + ':' + addLeadingZeros(sec)
}
const logOutUser = () => {
logout();
return history.push(mainRoute)
}
function setTimer() {
const timer = setTimeout(() => {
setTimmer(true)
console.log('This will run after 3 seconds!')
startCountdown()
}, sessionTimeout);
return () => clearTimeout(timer);
}
useEffect(() => {
if (isTimmerStoped === false) {
console.log('Effect Starting', isTimmerStoped)
setTimer()
} else {
console.log('Effect Stopping', isTimmerStoped)
stopCountdown()
}
}, [isTimmerStoped, setStopTimer, minutesToCountDown]);
return <React.Fragment>
<CssBaseline />
<Container disableGutters maxWidth={false}>
<NavigationBar handleSignOut={logOutUser}/>
<TimerContent
timeRemaining={convertSeconds(counterValue)}
isTimerAlertOpen={isTimerOpen}
extendSessionBtn={stopCountdown}
logoutBtn={logOutUser}
clickOutsideButton={stopCountdown}/>
</Container>
</React.Fragment>
}
export default Admin;
You should do 2 things.
Make the interval variable a ref. This way it's value will be unique every where it imported. Note: Just creating a variable above the component is a bad idea because that variable will be shared between each component that imports the Admin component, which will lead to bugs.
Wrong
let interval;
function Admin() {
//... code here
// STARTS THE COUNTDOWN
// var interval; Remove from here
const startCountdown = () => {
interval = setInterval(timeIt, 1000)
}
//... code here
}
export default Admin;
Right
function Admin() {
const interval = React.useRef();
//... code here
// STARTS THE COUNTDOWN
// var interval; Remove from here
const startCountdown = () => {
interval.current = setInterval(timeIt, 1000)
}
//... code here
}
export default Admin;
Add clearInterval to your stopCountdown function. You can remove the clearInterval in the timeIt function and move it into stopCountdown. Please take a look at this codepen I made to demostrate
const stopCountdown = () => {
console.log("Stop Timer")
setStopTimer(true);
setCounterValue(0);
setTimmer(false);
clearInterval(interval.current) // Clear the interval here
}
You shouldn't maintain the intervalId returned by setInterval in a functional variable since it will be reset on re-render and you will loose the actual timer Id. You must instead use useRef hook to store the timerId
const interval = useRef(null);
...
function timeIt() {
if (isTimmerStoped === false) {
transformMinutesToSeconds--
setCounterValue(transformMinutesToSeconds)
console.log("Timer is on: ", transformMinutesToSeconds)
if (transformMinutesToSeconds === 0) {
clearInterval(interval.current)
setStopTimer(true)
}
} else {
setStopTimer(true)
clearInterval(interval.current)
}
}
...
// STARTS THE COUNTDOWN
const startCountdown = () => {
interval.current = setInterval(timeIt, 1000)
}
I have the following statement
if (!this.customMsg) {
this.customMsg = setInterval(() => {
// doSomething();
}, 2000);
}
I want to do something like this;
this.customMsg = !this.customMsg && setInterval(() => {
// doSomething();
}, 2000);
The above way doesn't work, what am i doing wrong.
You can try this
this.customMsg || (this.customMsg = setInterval(function() {
}, 2000));