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kandi X-RAY | reactjs.org Summary
kandi X-RAY | reactjs.org Summary
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Top functions reviewed by kandi - BETA
- Creates a new redirects configuration file .
- Parse header ID
- Shared component to highlight .
- Generate the RSS feed .
- Creates a new error object .
- Add header ids to header strings
- Validate headers ids of the header ids .
- Show theme button .
- Example application application .
- Recursively walk a directory tree .
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Community Discussions
Trending Discussions on reactjs.org
QUESTION
I am trying to write a function that will handle getting data to and from a server. This function takes the url to contact and uses the token to authorize itself against the server. This function is quite long. I would therefore want every other page in my react app to call this function with the needed url and then let this function handle everything else. I therefore need each page to await this function but I get "Error: Invalid hook call" no matter what I try.
This is the function that handles post requests to the server:
...ANSWER
Answered 2022-Apr-07 at 09:58Its because you are using useContext() hook inside getProtectedAsset() function. Instead of using useContext inside getProtectedAsset try to pass user as parameter like url to the function.
QUESTION
I get this error every time I create a new React App and I don't know how to fix it:
Warning: ReactDOM.render is no longer supported in React 18. Use createRoot instead. Until you switch to the new API, your app will behave as if it's running React 17. Learn more: https://reactjs.org/link/switch-to-createroot
I created my react app using: npx create-react-app my-app
ANSWER
Answered 2022-Apr-05 at 08:44In your file index.js, change to:
QUESTION
I have a Json File which contains blog, when I am passing
...ANSWER
Answered 2022-Mar-10 at 17:44It appears you are using react-router-dom@6 so there are no longer any route props. In other words, props.match is undefined. Reading into props.match.params then throws the error.
Use the useParams hook to access the date route param.
QUESTION
I am unsure as to whether I should change my approach on how I render the components. I depend on a lot of modals that causes unnecessary re-renders when showing/hiding the modals.
This is a basic idea of how my components are currently being rendered:
I have cases where I can re-use the components (such as Component X in Component C and D), however there are cases (Component A3/B3 and Component E3) where the structure is completely different making it difficult to reuse the component. The problem I am encountering is slow UI due to multiple re-renders.
I display the modals based on state variables declared in their corresponding parent component. When changing the parent's state variable to display the modal causes the parent to re-render, and thus all of its children too. So as an example if I want to display the Create/Edit modal in Component A1, this will cause Component A, A2 and A3 to also re-render which is quite unnecessary. I have made use of the useMemo and useCallback hooks (https://reactjs.org/docs/hooks-reference.html#usememo) to help reduce the load, but I am unsure if this is the right approach? It feels like I am depending too much on the useMemo and useCallback hooks just to display a modal.
The idea behind the modals is to delete/edit/create a record that will display in the table (located in a different component). This is by design and I cannot change this.
To manipulate the data I am passing a callback function to each modal component. The modal component sends through the data being changed in the modal to the callback function where the data can be manipulated on the parent component.
...ANSWER
Answered 2022-Jan-16 at 08:28This is a case for React.memo. It is like the useMemo hook, but for components, and prevents re-renders of the component unless its props change:
QUESTION
The logout function is used to log out a user by making an API call and deleting this user's information from LocalStorage and from the Redux store. This function therefore uses two hooks: useDispatch and useFetch (custom hook)
...ANSWER
Answered 2022-Jan-05 at 09:56logout is not a function it's the hook, and you can't use hook inside the function, because when you do action={() => logout()} you are wrapping hook inside the function. Which is not valid in the function component.
QUESTION
By default, React preserves state of a component while it stays at the same position. Usually, this is exactly what you want, so it makes sense as the default behavior.
Examples are taken from the new React docs.
Example 1 - the same position, codesandbox, (relevant code) :
ANSWER
Answered 2021-Dec-07 at 02:29In the first example, both Counter will preserve the same state because the are rendered one at a time in the same exact position in DOM Tree. React thinks they are the same because the position. Latter by definition, Counter Taylor and Sarah are rendered at different location in DOM Tree. Therefore react thinks they are different and give them their own state.
Another option which produce same result as the second example is option 2 where even though they are switched in the same position, they have different keys therefore considered different.
Remember, react only sees component in DOM Tree and preserve their states only if they are rendered.
QUESTION
I've successfully written my application using Axios to fetch content. As of now, it's set up to fetch content when certain events happen (like the submit button has been clicked.) However, I'm experimenting with Redux's RTK-Query solution. This package generates hooks and in their examples, they provide simple component-level examples that call the hooks on mount.
How can I leverage these rtk-hooks (and hooks in general) so I can tie them to behaviors like onClick, onSubmit, and conditional events? I'm aware this conflicts with the rules-of-hooks guidelines, but I can't imagine RTK-Query would be so limited as to only allow component-level onMount API calls.
some related articles I'm reading while I try to figure this out / wait for a helpful example:
- https://blog.logrocket.com/react-hooks-frustrations/
- https://redux-toolkit.js.org/rtk-query/usage/usage-without-react-hooks
The second article seems somewhat relevant but I feel like its beating too far off the path and is making question if it's even worth having rtk-query installed. I might as well just use axios since it can be used anywhere in my components and logic. Can someone educate me on how to approach this problem? I'm new to rtk-query, it seems really cool but it also seems really restrictive in its implementation approaches.
api.ts slice:
...ANSWER
Answered 2021-Sep-08 at 07:49If you use a query, you would use local component state to set the query parameter
QUESTION
Wanting to improve my understanding of React in functional components I've seen some that pass a seState with a function when spreading an array or object. When I reference the docs I see:
Unlike the
setStatemethod found in class components,useStatedoes not automatically merge update objects. You can replicate this behavior by combining the function updater form with object spread syntax
So I'm trying to understand why this implementation:
...ANSWER
Answered 2021-Nov-12 at 16:04Its probably best practice to pass a function to the useState dispatch to avoid renders getting out of sync, especially if you use asynchronous methods to update state, but also any time your new state is dependent on previous state (so like even incrementing numbers, not just for objects and arrays).
As Kent C. Dodds illustrates, there are issues as it comes to closures and the timing of rendering and function calls when the new state update is dependent upon previous state.
If you want to merge your data with previous state, you want to be sure to merge with the latest state (as of that particular merge call). The setState dispatch provides the previous state as the first parameter. You can be certain that this is the latest state (for that merge) and you won't get out of sync data, or out of order updates.
QUESTION
I've been working with Javascript for a couple of years now, and with my current knowledge of the event loop I'm struggling to understand why this testing recipe from the React docs work. Would someone be able to break down exactly what happens in each step there? To me, it seems magical that this works in the test:
...ANSWER
Answered 2021-Nov-02 at 10:43When looking closer at the source code of react-dom and react-dom/test-utils it seems like what's making this whole thing work is this setImmediate call happening after the first effect flush in recursivelyFlushAsyncActWork.
It seems like act chooses to use this recursivelyFlushAsyncActWork simply because the callback has the signature of being "thenable", i.e. a Promise. You can see this here.
This should mean that what happens is (simplified) this:
- The
useEffectcallback is flushed (puttingfetchon the event loop). - The
setImmediatecallback "ensures" our mock promise / fetch is resolved. - A third flush happens by a recursion inside the
setImmediatecallback (called byenqueueTask) making the state changes appear in the DOM. - When there's nothing left to flush it calls the outer most
resolveand ouractresolves.
In the code that looks kinda like this (except this is taken from an older version of react-dom from the node_modules of my React project, nowadays flushWorkAndMicroTasks seems to be called recursivelyFlushAsyncActWork):
QUESTION
I'm learning to create an NPM Libraries and publish to NPM. I followed this tutorial.
Here's a Codesandbox that works OK but can't test the npm link there.
It's working - I can use my published to NPM, npm package simply doing like so:
...ANSWER
Answered 2021-Oct-23 at 23:55I fixed it by reading the docs.
This problem can also come up when you use npm link or an equivalent. In that case, your bundler might “see” two Reacts — one in application folder and one in your library folder. Assuming myapp and mylib are sibling folders, one possible fix is to run npm link ../myapp/node_modules/react from mylib. This should make the library use the application’s React copy.
The first error:
Was that in the package.json I did not change "main" to the src folder. Just doing that and npm link to peer app node_folders React fixed this problem.
(Just don't forget after "npm run build" of the lib to change back the package.json "main" to src folder.
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