react-hooks

问题 Current useEffect is fired when just one of the dependencies have changed. How could I update it / use it to fire back when both ( or all ) of the dependencies have changed? 回答1: You'll need to add some logic to call your effect when all dependencies have changed. Here's useEffectAllDepsChange that should achieve your desired behavior. The strategy here is to compare the previous deps with the current. If they aren't all different, we keep the previous deps in a ref an don't update it until

问题 I am trying to figure out as many ways as possible to optimize flatlist since my flatlist component complains my flat list items takes too long to render (I am already using removeClippedSubviews, windowSize, maxToRenderPerBatch, React.memo etc.). Is it good idea to wrap render function with useCallback? For example, lets say I have function component originally in form: const FlatListItem = ({ color1, color2, color3, color4 }) => { function renderViewWithColorLogic(color) { // do some

问题 I am trying to figure out as many ways as possible to optimize flatlist since my flatlist component complains my flat list items takes too long to render (I am already using removeClippedSubviews, windowSize, maxToRenderPerBatch, React.memo etc.). Is it good idea to wrap render function with useCallback? For example, lets say I have function component originally in form: const FlatListItem = ({ color1, color2, color3, color4 }) => { function renderViewWithColorLogic(color) { // do some

问题 I am trying to figure out as many ways as possible to optimize flatlist since my flatlist component complains my flat list items takes too long to render (I am already using removeClippedSubviews, windowSize, maxToRenderPerBatch, React.memo etc.). Is it good idea to wrap render function with useCallback? For example, lets say I have function component originally in form: const FlatListItem = ({ color1, color2, color3, color4 }) => { function renderViewWithColorLogic(color) { // do some

问题 I am trying to figure out as many ways as possible to optimize flatlist since my flatlist component complains my flat list items takes too long to render (I am already using removeClippedSubviews, windowSize, maxToRenderPerBatch, React.memo etc.). Is it good idea to wrap render function with useCallback? For example, lets say I have function component originally in form: const FlatListItem = ({ color1, color2, color3, color4 }) => { function renderViewWithColorLogic(color) { // do some

问题 I'm making an authentication system and after backend redirects me to the frontend page I'm making api request for userData and I'm saving that data to localStorage. Then I'm trying to load Spinner or UserInfo. I'm trying to listen for localStorage value with useEffect but after login and I'm getting 'undefined'. When localStorage value is updated useEffect do not run again and Spinner keeps spinning forever. I have tried to do: JSON.parse(localStorage.getItem('userData')) , and then I got

问题 I'm making an authentication system and after backend redirects me to the frontend page I'm making api request for userData and I'm saving that data to localStorage. Then I'm trying to load Spinner or UserInfo. I'm trying to listen for localStorage value with useEffect but after login and I'm getting 'undefined'. When localStorage value is updated useEffect do not run again and Spinner keeps spinning forever. I have tried to do: JSON.parse(localStorage.getItem('userData')) , and then I got

问题 I have a React functional component that is using forwardRef like this: const wrapper = React.forwardRef((props, ref) => ( <MyComponent {...props} innerRef={ref} /> )); export default wrapper; Now I want to pass some state to this component using mapStateToProps with Redux's connect function like this: export default connect(mapStateToProps, null)(MyComponent); I tried to combine them in the following way but it didn't work: const wrapper = React.forwardRef((props, ref) => ( <MyComponent {..

问题 I have a React functional component that is using forwardRef like this: const wrapper = React.forwardRef((props, ref) => ( <MyComponent {...props} innerRef={ref} /> )); export default wrapper; Now I want to pass some state to this component using mapStateToProps with Redux's connect function like this: export default connect(mapStateToProps, null)(MyComponent); I tried to combine them in the following way but it didn't work: const wrapper = React.forwardRef((props, ref) => ( <MyComponent {..

问题 I want to show input results when I focused on this input and hide this result when I blur. I 'v used this code but not work with blur useEffect(() => { if (inputElMovie.current.focus) { console.log("meme") } }, [movies,inputElMovie]); 回答1: You don't need useEffect for this case. Create a custom hook with useState() , and return a boolean ( show ), and an object of event handlers you can spread on the input: const { useState, useMemo } = React const usToggleOnFocus = (initialState = false) =>