react-hooks

问题 In the effort to better learn React, TypeScript, and Context / Hooks, I'm making a simple Todo app. However, the code needed to make the context feels cumbersome. For example, if I want to change what a Todo has, I have to change it in three places (ITodo interface, default context value, default state value). If I want to pass down something new, I have to do that in three places (TodoContext, TodoContext's default value, and value=). Is there a better way to not have to write so much code?

问题 I am facing a problem that I've tried to solve in lots of different ways, but I cannot get it to work. Please see this Expo application, I've created a dumb example that demonstrates my problem: https://snack.expo.io/HJB0sE4jS To summarize, I want to build an app with a draggable component (The blue dot in the example), but while the user drags the component I also need to update the state of the app (the counter in the example). The problem is that whenever the state updates during dragging,

问题 I am facing a problem that I've tried to solve in lots of different ways, but I cannot get it to work. Please see this Expo application, I've created a dumb example that demonstrates my problem: https://snack.expo.io/HJB0sE4jS To summarize, I want to build an app with a draggable component (The blue dot in the example), but while the user drags the component I also need to update the state of the app (the counter in the example). The problem is that whenever the state updates during dragging,

问题 I am facing a problem that I've tried to solve in lots of different ways, but I cannot get it to work. Please see this Expo application, I've created a dumb example that demonstrates my problem: https://snack.expo.io/HJB0sE4jS To summarize, I want to build an app with a draggable component (The blue dot in the example), but while the user drags the component I also need to update the state of the app (the counter in the example). The problem is that whenever the state updates during dragging,

问题 I have been using React and D3 separately and now have a project where I need low level control over the plotting function of an application. Basically, I need to be able to go and fetch higher resolution data from a database as the user zooms in, and vice versa as the user zooms out, on a plot. I have found a few methods to use D3 and React together. I wanted to try and keep all of my React code based around the hooks API as that is what is used for the rest of the code base. I am struggling

问题 My use state variable, query , inside of the function isExternalFilterPresent never updates. I'm perplexed because the first console.log of query updates with each change of query. I think this is because I'm not quite understand the implementation of hooks. let gridApi: GridApi | null = null; const HouseholdTable = ({accountsData, aggregateEntityTable: {aggregateEntity, columnDefs}}: OwnProps & StateProps) => { const [isDeepDiveOpen, setIsDeepDiveOpen] = useState(false); const [query,

问题 As far as I've known, functions that defined in a React's functional component are regenerated whenever the component rerenders. Since useCallback can be triggered by specific dependencies, it prevents unnecessary regeneration of these functions. Should I wrap each of them in useCallback, and pass relevant dependencies? import React from 'react' const Comp = () => { const fn1 = useCallback( ()=>{ // do something 　　　}, [dependency1]) const fn2 = useCallback( ()=>{ // do something 　　　},

问题 As far as I've known, functions that defined in a React's functional component are regenerated whenever the component rerenders. Since useCallback can be triggered by specific dependencies, it prevents unnecessary regeneration of these functions. Should I wrap each of them in useCallback, and pass relevant dependencies? import React from 'react' const Comp = () => { const fn1 = useCallback( ()=>{ // do something 　　　}, [dependency1]) const fn2 = useCallback( ()=>{ // do something 　　　},

问题 Setup/Scenario I am using twitter api to fetch data and rendering it in twitter card using react-native-socials. The tweet data ( JSON ) is stored and served through my backend and rendered in the app. I am using a Flatlist to render this data. Problem It's working fine for the first 3 loads, I am using pullToRefresh in flatlist to do a network call to get new data. But when I try the 4th time it gets an undefined element. I've replaced the Twitter element ( from react-native-socials lib )

问题 Setup/Scenario I am using twitter api to fetch data and rendering it in twitter card using react-native-socials. The tweet data ( JSON ) is stored and served through my backend and rendered in the app. I am using a Flatlist to render this data. Problem It's working fine for the first 3 loads, I am using pullToRefresh in flatlist to do a network call to get new data. But when I try the 4th time it gets an undefined element. I've replaced the Twitter element ( from react-native-socials lib )