If the value of props.filters did not change, then React would skip the effect. // This will only re-run if the value of `props.filters` changes useEffect(() => { fetchSomeData(props.filters); }, [props.filters]); With hooks, React does this internally unlike the implementation using componentDidUpdate where we have to compare the value of prevProps and nextProps against each … Read more
That issue is caused by many updates inside Component. I got the same issue, this would solve the issue. await act( async () => mount(<App />));
It won’t re-render the component if you call setState with the same value. Try this out: import React, { useState, useEffect } from “react”; const foo = { foo: ‘bar’ }; export default ({ name }) => { const [state, setState] = useState(foo); console.log(“rendered!”); useEffect(() => { setState(foo); console.log(“state reset!”); }); const handleClick = () … Read more
Effects created using useEffect are run after the render commit phase and hence after the render cycle. This is to make sure that no side-effects are executed during the render commit phase which might cause inconsistency According to the documentation Mutations, subscriptions, timers, logging, and other side effects are not allowed inside the main body … Read more
refs are basically objects, and they have a default key current. So, you can create an array of refs like this: const myRefs= useRef([]); Then you can populate this array of refs like this: ref={el => (myRefs.current[i] = el)} Here is the full version: { [1, 2, 3].map((v, i) => { return ( <button ref={(el) … Read more
I got the same error. And, the following worked for me. getOptionLabel={(option) => option.name || “”}
You’re missing the dependencies in your hook. Try this: useEffect(() => { const onScroll = e => { setScrollTop(e.target.documentElement.scrollTop); setScrolling(e.target.documentElement.scrollTop > scrollTop); }; window.addEventListener(“scroll”, onScroll); return () => window.removeEventListener(“scroll”, onScroll); }, [scrollTop]); By moving onScroll inside the useEffect, you don’t need to track it on the hook’s dependencies, however since it uses scrollTop from the … Read more
You want to initiate a timeout function inside a lifecycle method. Lifecycle methods are methods which call on, for example, mount and unmount (there are more examples but for the sake of explanation I will stop here) what you’re interested in is the mount lifecycle. In functional components, it can be accessed like this: import … Read more
In your case it doesn’t really makes sense to memoize Child because if item changes, the child has to re-render. However if there is a case that props do not change , but still the child is re-rendering due to the functions getting recreated you would make use of useCallback hook to memoize the functions, … Read more
Yes, as far as passing down props are concerned there is no difference in usage with React Hooks. In the snippet you’ve provided just pass setSearchData as a prop to PostContainer. <PostContainer data={dataOnMap} addLike={addLike[index]} searchData={searchData} setSearchData={setSearchData} />