The useEffect cleanup is a function in the useEffect Hook that allows us to tidy up our code before our component unmounts. When our code runs and reruns for every render, useEffect also cleans up after itself using the cleanup function. Which of the foloowing is the correct Pseudo code for it?AuseEffect(() => { //effect //cleanup }, [input])BuseEffect(() => { // effect }, [cleanup])CuseEffect(() => { effect return () => { cleanup } }, [input])DNone of the above
Question
The useEffect cleanup is a function in the useEffect Hook that allows us to tidy up our code before our component unmounts. When our code runs and reruns for every render, useEffect also cleans up after itself using the cleanup function. Which of the foloowing is the correct Pseudo code for it?AuseEffect(() => { //effect //cleanup }, [input])BuseEffect(() => { // effect }, [cleanup])CuseEffect(() => { effect return () => { cleanup } }, [input])DNone of the above
Solution
The correct pseudo code for the useEffect cleanup function is:
C
useEffect(() => {
// effect
return () => {
// cleanup
}
}, [input])
Similar Questions
What is the correct syntax of useEffect cleanup function?AuseEffect(() => { // effect return () => { // cleanup }}, [input])BuseEffect(() => { // effect // cleanup return () => { }}, [input])CuseEffect(() => { // effect return () => { }}, cleanup, [input])DNone of the above
What happens if the cleanup function in the useEffect() hook returns a function?AThe returned function is ignoredBThe returned function is called before the effect runsCThe returned function is called after the effect runs and before the component unmountsDThe returned function is called after the component unmounts
Which of the following is the correct syntax for using the useEffect() hook with a cleanup function to start a timer?AuseEffect(() => { const timer = setInterval(() => { setCount(count + 1) }, 1000); return clearInterval(timer)}, [])BuseEffect(() => { const timer = setInterval(() => { setCount(count + 1) }, 1000); return () => clearInterval(timer)}, [])CuseEffect(() => { const timer = setInterval(() => { setCount(count + 1) }, 1000) }, [count]; return clearInterval(timer))DuseEffect(() => { const timer = setInterval(() => { setCount(count + 1) }, 1000) }, [count];return () => clearInterval(timer))
Which of the following code subscribes to the user in useEffect and then signout him in useEffect cleanup?AuseEffect(() => { // set our variable to true let isSubscribed = true; get(API).then((response) => { if (isSubscribed) { // handle success } }); return () => { // cancel the subscription isSubscribed = false; };}, []);BuseEffect(() => { // set our variable to true let isSubscribed = true; get(API).then((response) => { if (isSubscribed) { // handle success } }); return () => { // cancel the subscription isSubscribed = true; };}, []);CuseEffect(() => { // set our variable to true let isSubscribed = true; get(API).then((response) => { if (isSubscribed) { // handle success } });}, []);DuseEffect(() => { // set our variable to true let isSubscribed = true; if (!isSubscribed) { // handle success } return () => { // cancel the subscription isSubscribed = true; };}, []);
Which of the following code for useEffect() will be rendered only once when the component gets mounted ?AuseEffect(() => {console.log("Running")}, []);BuseEffect(() => {console.log("Running")});CuseEffect(() => {console.log("Running")}, [a]);DNone of the above
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