Answers for "running useeffect only once react native"

react run useeffect only once

useEffect(() => {
    // Initialization code comes here
}, []);

running useeffect only once react native

useEffect(() => {
    // This will run only once when the component mounts
}, []);

Explaination useEffect vs. componentDidMount

componentDidMount became a popular lifecycle function in class components 
because it was the ideal way to fetch data for the component. This is something 
that both useEffect and componentDidMount have in common.

However, componentDidMount is only supposed to run at the beginning of the 
lifecycle and then become dormant. useEffect runs when the component mounts but
also can run at any time when dependencies change. Therefore, if no 
dependencies are passed to the second argument array, or if the dependencies 
always change, the function continues to run (sometimes causing an infinite 
                                               loop).

To have the useEffect only run once when the component mounts remember to pass 
an empty array as the second argument (or pass an array with the necessary 
                                       dependencies).