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
Question
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
Solution
The correct answer is A.
useEffect(() => {console.log("Running")}, []);
This is because the second argument to useEffect is an array of dependencies. If this array is empty, like in option A, the effect will only run once, similar to componentDidMount.
Option B will run the effect after every render, because it doesn't have a second argument.
Option C will run the effect every time the variable 'a' changes, because 'a' is listed as a dependency.
So, the code that will be rendered only once when the component gets mounted is option A.
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