Yes, the behavior is similar. React is batching the updates calls. When Writing: const handleClick = () => setCount(count + 1) handleClick() handleClick() handleClick() the count in state will be 1 When Writing: const handleClick = () => setCount(prevCount => { return prevCount + 1; }); handleClick() handleClick() handleClick() the count in state will be … Read more
It’s an intentional feature of the StrictMode. This only happens in development, and helps find accidental side effects put into the render phase. We only do this for components with Hooks because those are more likely to accidentally have side effects in the wrong place. — gaearon commented on Mar 9, 2019
That issue is caused by many updates inside Component. I got the same issue, this would solve the issue. await act( async () => mount(<App />));
value is stale in the event handler because it gets its value from the closure where it was defined. Unless we re-subscribe a new event handler every time value changes, it will not get the new value. Solution 1: Make the second argument to the publish effect [value]. This makes the event handler get the … Read more
useRef is just partially similar to React’s ref(just structure of object with only field of current). useRef hook is aiming on storing some data between renders and changing that data does not trigger re-rendering(unlike useState does). Also just gentle reminder: better avoid initialize hooks in loops or if. It’s first rule of hooks. Having this … Read more
This is best used when you want to prevent unnecessary re-renders for better performance. Compare these two ways of passing callbacks to child components taken from React Docs: 1. Arrow Function in Render class Foo extends Component { handleClick() { console.log(‘Click happened’); } render() { return <Button onClick={() => this.handleClick()}>Click Me</Button>; } } 2. Bind … Read more
I came across this problem myself and managed to fix it by passing a key to the React-Select component, with the selected value appended to it. This will then force the ReactSelect to re-render itself when the selection is updated. I hope this helps someone. import ReactSelect from ‘react-select’; … <ReactSelect key={`my_unique_select_key__${selected}`} value={selected || ”} … Read more
Much like setState, the state update behaviour using hooks will also require a re-render and update and hence the change will not be immedialtely visible. If however you try to log state outside of the handleVisibleChange method, you will see the update state export const NodeMenu: React.SFC<NodeMenuProps> = props => { const [isVisible, setIsVisible] = … Read more
It would be better to add an event listener for localstorage here. useEffect(() => { function checkUserData() { const item = localStorage.getItem(‘userData’) if (item) { setUserData(item) } } window.addEventListener(‘storage’, checkUserData) return () => { window.removeEventListener(‘storage’, checkUserData) } }, [])
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