Originally, we only tracked reactions on the client side and did not persist them to the server. The top one will only update after a successful mutation and resync with the server. (This is more important if you're using TypeScript, because only the extendedApiSlice value has the added types for the new endpoints.). We need a way to force a refetch of both the individual Post entry, and the entire list of posts. // In this case, `getPost` will be re-run. We can do that same process using RTK Query. Thanks for reading through this tutorial, and we hope you enjoy building applications with Redux! I trigger mutation in the first component and I need to get results in the second component. This will look much like the mutation for adding a post, but the endpoint needs to include the post ID in the URL and use an HTTP PATCH request to indicate that it's updating some of the fields. We need to update that to import the extended API slice instead: Alternately, you could just export the specific endpoints themselves from the slice file. Config API Reference importBaseApiFrom The result object has a data field inside with the actual values we need, as well as some of the request metadata fields. We can rewrite notificationsSlice so that it listens for any received notifications, and tracks some additional state on the client side for each notification entry. RTK Query Examples Examples Overview We have a variety of examples that demonstrate various aspects of using RTK Query. The second is an object that contains some of the same fields as the thunkApi in createAsyncThunk ( {dispatch, getState, extra, requestId}), but also a Promise called queryFulfilled. RTK Query is an experimental library from the Redux team with the main purpose of fetching and caching data for your web app. We initially faked that feature by adding a "Refresh Notifications" button, and having it make an HTTP GET request for more notifications entries. However, RTK Query saves each query result independently in the cache. We currently have selectors like selectAllUsers and selectUserById that are generated by our createEntityAdapter users adapter, and are reading from state.users. Instead of exporting selectAll as selectAllNotifications, we're going to export it as selectNotificationsMetadata. This approach of updating client state right away is called an "optimistic update", and it's a common pattern in web apps. The onQueryStarted method can be used for optimistic updates. , Feel free to reach out for anything!liad_shiran, A publication by the Nielsen Tel Aviv Engineering team, where we talk about what we do and how we do things, Frontend Software Engineer, writer, open-source contributor, Toward the minimum viable decoupled website, What the function? The last component that is reading from the old postsSlice is , which filters the list of posts based on the current user. // The `LIST` id is a "virtual id" we just made up to be able to invalidate this query specifically if a new `Posts` element was added. Our component has to initiate the fetching of notifications, and needs to show the notification entries with the correct read/unread status. For example, filter state, search term, toggle state, pagination state, etc. This can be useful if you wish to determine whether the mutation succeeds/fails inline at the call-site. We can use the same useGetPostQuery hook that we used in to read the Post entry from the cache in the store, and we'll use the new useEditPostMutation hook to handle saving the changes. As we go through, we'll see how to use all the major features of RTK Query, as well as how to migrate existing uses of createAsyncThunk and createSlice over to use the RTK Query APIs. Ideally, we want to use the same logic in response to both cases. But if I want to use React Hooks to make the call I'll need the result from the login mutation beforehand. Switching these to use RTK Query will give us a chance to try out some of the advanced techniques available for working with RTK Query's cached data, and allow us to provide a better experience for our users. Endpoints can define an onQueryStarted function that will be called when a request starts, and we can run additional logic in that handler. So, we'll import createAction, define a new action type specifically for the "received some notifications" case, and dispatch that action after updating the cache state. Inside of there, we add a new "read/isNew" metadata entry that corresponds to each notification by ID, and store that inside of notificationsSlice. They can handle any global state that is not server data. RTK Query allows multiple components to subscribe to the same data, and will ensure that each unique set of data is only fetched once. There's a couple ways that we could handle this conceptually. In this video we will explore the Redux Toolkit RTK Query and Mutations in detail with example. Finally, we need change the selectors we're exporting from this slice. Try refreshing the page and clicking through the posts list and single post view. We've already added a mutation endpoint to save new Post entries to the server, and used that in our . So, we can create a cache selector with no argument, and the cache key becomes undefined. That way, every time we add a new post, we force RTK Query to refetch the entire list of posts from the getQuery endpoint. The providesTags field can also accept a callback function that receives the result and arg, and returns an array. The correct user names should appear in each displayed post, and in the dropdown in the . As an example, say that we have an API slice with getTodos and getTodo endpoints, and our components make the following queries: Each of these query results would include a Todo object that looks like {id: 1}. There's not a lot of information in the official docs at the moment, on how to test RTK Query. Check out the PostDetail component for an example of Class Component usage. In order to get the right behavior, we need to set up each endpoint with the right tags: It's possible for the result argument in these callbacks to be undefined if the response has no data or there's an error, so we have to handle that safely. We've now seen three different ways that we can manage transforming responses: Each of these approaches can be useful in different situations. In Part 6: Performance and Normalization, we discussed reasons why it's useful to store data in a normalized structure. In this case, our getUsers endpoint doesn't need any parameters - we always fetch the entire list of users. We're going to repurpose this slice to instead store "metadata" objects that describe the read/unread status. Try adding an appearsIn field to the hero object in the query, and see the new result. If the timer expires before any new subscriptions for the data are added, RTK Query will remove that data from the cache automatically, because the app no longer needs the data. As long as 1+ subscribers for the data are still active, the cache entry is kept alive. Mutations can also invalidate cached data and force re-fetches. Thank you in advance! Our similarly switches over to reading the cached data and metadata. // To generate a selector for a specific query argument, call `select(theQueryArg)`. To take full advantage of it, we can, and should, use RTKQ for all requests. It gives us access to the original promise object of the request ( queryFulfilled) and we can either await it or use Promise.all with it along with other promises. Please note that when playing with the examples in CodeSandbox that you can experience quirky behavior, especially if you fork them and start editing files. The is still using the cached Post entry that was fetched earlier. The "mutation result" is an object containing properties such as the latest data for the mutation request, as well as status booleans for the current request lifecycle state. Dispatching an action to set the user state. Serving cached data while avoiding duplicate requests for the same data. Earlier, we saw how we can use "tags" to invalidate parts of our cached data. There are several ways to handle authentication with RTK Query. By default, unused data is removed from the cache after 60 seconds, but this can be configured in either the root API slice definition or overridden in the individual endpoint definitions using the keepUnusedDataFor flag, which specifies a cache lifetime in seconds. Currently, we're reading the Post entry with selectPostById, and manually dispatching a postUpdated thunk for the request. I hope I have provided you with some helpful insights on the matter! Since result is being kept in the Redux store, we can't mutate it - we need to return a new object. For getPosts we can do that by using a default argument array value to map over, and for getPost we're already returning a single-item array based on the argument ID. But, this issue has nothing to do with RTKQ itself. All of the data fetching has been switched over to use RTKQ, and we've improved the user experience by adding optimistic updates and streaming updates. Normally, selectors expect the entire Redux state as their first argument, and extract or derive a value from state. Our src/api/server.js file has a mock Websocket server already configured, similar to the mock HTTP server. // In this case, the users query has no params, so we don't pass anything to select(), /* Temporarily ignore selectors - we'll come back to this later, } = usersAdapter.getSelectors((state) => state.users), import { apiSlice } from './features/api/apiSlice', import { extendedApiSlice } from './features/users/usersSlice', await worker.start({ onUnhandledRequest: 'bypass' }), store.dispatch(apiSlice.endpoints.getUsers.initiate()), store.dispatch(extendedApiSlice.endpoints.getUsers.initiate()), // Return a unique selector instance for this page so that, // the filtered results are correctly memoized, // Use the same posts query, but extract only part of its data, // We can optionally include the other metadata fields from the result here. These are the best practices, in my opinion, for the most commonly asked questions I heard from my peers while introducing RTK Query. RTK Query provides advanced setup options to handle your fetching and caching needs in the most flexible and efficient way possible. It still returns an array of the values from the normalized state, but we're changing the name since the items themselves have changed. // Include a field called `postsForUser` in the hook result object, // which will be a filtered list of posts, // In a real app, we'd probably need to base this on user ID somehow, // so that a user can't do the same reaction more than once. RTK Query takes a more centralized approach to this and requires you to configure the invalidation behavior in your API service definition. Mutation endpoints are defined by returning an object inside the endpoints section of createApi, and defining the fields using the build.mutation() method. Inside of onCacheEntryAdded, we create a real Websocket connection to localhost. When the cache entry is removed, we clean up the Websocket subscription. RTK Query allows multiple components to subscribe to the same data, and will ensure that each unique set of data is only fetched once. Because query hooks add an additional refetch method to whatever is returned here, it's preferable to always return an object from selectFromResult with the fields inside that you need. In the example below you'll notice a few things. Like with onQueryStarted, the onCacheEntryAdded lifecycle handler receives the arg cache key as its first parameter, and an options object with the thunkApi values as the second parameter. Endpoints can define a transformResponse handler that can extract or modify the data received from the server before it's cached. RTK Query hooks comes with a host of other return values like isFetching and isError, so check out the docs for queries and mutations to see what's available. We will build a React Client with React Query and Axios library to make CRUD requests to Rest API in that: React Query Axios GET request: get all Tutorials, get Tutorial by Id, find Tutorial by title. Go to the main , and click one of the reactions to see what happens. If you're looking for help with Redux questions, come join the #redux channel in the Reactiflux server on Discord. When we clicked on "Edit Post", the component was unmounted by the router, and the active subscription was removed due to unmounting. It's common for clients to need to extract pieces of data from the server response, or to transform the data in some way before caching it. RTK Query is a powerful data fetching and caching tool. // `updateQueryData` requires the endpoint name and cache key arguments, // so it knows which piece of cache state to update, // The `draft` is Immer-wrapped and can be "mutated" like in createSlice, // create a websocket connection when the cache subscription starts, // wait for the initial query to resolve before proceeding. The two hook usages will return the exact same results, including fetched data and loading status flags. This is deliberately more visible because our mock API server is set to have a 2-second delay before responding, but even if the response is faster, this still isn't a good user experience. section in Part 6 has links to additional resources for app ideas, tutorials, and documentation. Since this example app is small, we'll just give the name of the reaction, and let the server increment the counter for that reaction type on this post. Copyright 20152022 Dan Abramov and the Redux documentation authors. RTK Query is a powerful data fetching and caching tool. We want to run the same "add read/new metadata" logic for both the "fulfilled getNotifications" action and the "received from Websocket" action. We're currently defining a fetchUsers async thunk in usersSlice.js, and dispatching that thunk manually in index.js so that the list of users is available as soon as possible. // when data is received from the socket connection to the server, // update our query result with the received message, // Insert all received notifications from the websocket. Since the usersSlice is no longer even being used at all, we can go ahead and delete the createSlice call from this file, and remove users: usersReducer from our store setup. Compared to popular alternatives like React-Query, the main strength of RTK Query is its default integration with the redux store. So far, all of our query endpoints have simply stored the response data from the server exactly as it was received in the body. For more info, check out: Defining an API slice. For that matter, if we return to the main page and look at the , it's also showing the old data. smooth muscle relaxant for cats 11; central carolina community foundation 2; Now, instead of potentially five files to fetch data and cache it in the Redux store, we need one. RTK Query provides an option to share results across mutation hook instances using the Mutations are used to send data updates to the server and apply the changes to the local cache. With that said, we might still need an async action if we dont want our logic to depend on a single endpoint, and be more generic (e.g., bootstrapping a page with some requests). In this case, the data is nested down inside the RTK Query cache reducer, so we select the right field out of the cache state. In my opinion, connecting more components to the store is not a bad practice and also improves performance. In this app, the notifications cache entry will never be removed because we never unsubscribe from the data, but it's important to see how the cleanup would work for a real app. In case the request fails, we can await queryFulfilled, catch a failure, and undo the patch changes to revert the optimistic update. The example has some intentionally wonky behavior when editing the name of a post, there is a decent chance you'll get a random error. When we save the edited post this time, we should see two requests happen back-to-back: Then, if we click back to the main "Posts" tab, we should also see: Because we provided the relationships between the endpoints using tags, RTK Query knew that it needed to refetch the individual post and the list of posts when we made that edit and the specific tag with that ID was invalidated - no further changes needed! /* Temporarily ignore adapter - we'll use this again shortly, const usersAdapter = createEntityAdapter(), const initialState = usersAdapter.getInitialState(), // Calling `someEndpoint.select(someArg)` generates a new selector that will return. This is a modified version of the complete example you can see at the bottom of the page to highlight the updatePost mutation. At this point, apiSlice and extendedApiSlice are the same object, but it can be helpful to refer to the extendedApiSlice object instead of apiSlice here as a reminder to ourselves. We can use selectFromResult to have read just a filtered list of posts from the cache. In case we need a special treatment for an error of a specific endpoint, we can do it with onQueryStarted by catching the error on the queryFulfilled promise: Each endpoint provides a select function that returns a selector for its cached data from the store (this selector may receive a cache key as an argument, which is the same argument we would call the query hooks with). However, if a new subscription is added before the timer expires, the timer is canceled, and the already-cached data is used without needing to refetch it. However, in this case we're only dealing with the "result" value that is kept in the cache. // Triggering `updatePostOne` will affect the result in this component, // but not the result in `ComponentTwo`, and vice-versa. // Example: `updatePost().unwrap().then(fulfilled => console.log(fulfilled)).catch(rejected => console.error(rejected)), // Execute the trigger with the `id` and updated `name`, // Or from '@reduxjs/toolkit/query' if not using the auto-generated hooks. This allows us to create tag entries based on IDs of data that is being fetched. RTK Query provides an onCacheEntryAdded endpoint lifecycle handler that lets us implement "streaming updates" to cached data. The query hooks also give us the ability to select pieces of the cached state by providing a selectFromResult option, and only re-render when the selected pieces change. The useMutation hook returns a tuple containing a "mutation trigger" function, as well as an object containing properties about the "mutation result". That will be useful when we try to use this data in the UI. When we dispatch that action, the return value is a patchResult object. In the example from https://redux-toolkit.js.org/rtk-query/usage/examples#using-extrareducers a extraReducer in autSlice.ts that is called when the login mutation in services/auth.js is intially called with credentials of Type LoginRequest as its action.payload. See Advanced Invalidation with abstract tag IDs for details on advanced invalidation handling with RTK Query. This should be a unique string shared between each mutation hook instance you wish to share results. Now that we're fetching data for RTK Query's cache, we should replace those selectors with equivalents that read from the cache instead. Defining an API Slice Similarly, invalidatesTags can be a callback as well. With that in place, let's update to use this mutation. Keeping. RTK Query has many other options for controlling when and how to refetch data, including "conditional fetching", "lazy queries", and "prefetching", and query definitions can be customized in a variety of ways. Let' see what notificationsSlice looks like after we add this logic. On my api I have two mutations and strangely, one of them does trigger the refetch but the other doesn't and I have no clue why. - https://youtu.be/qNjNn9BCWCcLearn React Redux Thunk with Project - https://youtu.be/JDZRfLGNWdcLearn React Hooks - https://youtu.be/hJ5UEtdS8qE Social Medias Twitter: https://twitter.com/IMDmalviaFacebook: https://www.facebook.com/programmingwithdipeshInstagram: https://www.instagram.com/dipeshmalviaLinkedIn: https://www.linkedin.com/in/dmalvia/ Tags - Learn Redux RTK Query- Redux Toolkit RTK Query Overview - RTK Query for beginners- Mutations in RTK Query- How to use Redux RTK Query Auto-fetching Hashtags #react #redux #toolkit #RTK #dipeshmalvia #tutorialDisclaimer:It doesn't feel good to have a disclaimer in every video but this is how the world is right now. However, in order for selectFromResult to avoid unnecessary re-renders, we need to ensure that whatever data we extract is memoized correctly. The adapter.getSelectors() function needs to be given an "input selector" so it knows where to find that normalized data. If we want to fetch the list of users outside of React, we can dispatch the getUsers.initiate() thunk in our index file: This dispatch happens automatically inside the query hooks, but we can start it manually if needed. For example, what if the /getPost request returns a body like {post: {id}}, with the data nested? For a mutation, subsequent calls are not assumed to be necessarily related, so a mutation is either 'loading' or 'not loading', with no concept of 're-fetching'. You can look at the examples from this repository. To illustrate this process, let's switch the getUsers endpoint to be injected in usersSlice.js, instead of defined in apiSlice.js. We can integrate createEntityAdapter into our extendedApiSlice, and actually use createEntityAdapter to transform the data before it's cached. Below are some of the most frequently used properties on the "mutation result" object. In the real world, it's very common that a developer would want to resync their local data cache with the server after performing a mutation (aka "revalidation"). Once we call a mutation endpoint that is defined to invalidate this tag, all of the query endpoints that have this tag will automatically refetch and update the cache (the store). Now, if we click several times on a reaction button quickly, we should see the number increment in the UI each time. The generated selector uses that cache key to know exactly which cached result it should return from the cache state in the store. The first item in the tuple is the "trigger" function and the second element contains an object with status, error, and data. Unlike useQuery, useMutation returns a tuple. As a final step, we can do some additional cleanup here - the postsSlice is no longer being used, so that can be removed entirely. From my experience with RTKQ, onQueryStarted is very useful and can replace most of the redux async middleware in the application (e.g. Next Steps This example only. There's a key difference with the memoized selector function we've created here. The endpoint.select() function in the API slice endpoints will create a new memoized selector function every time we call it. If the query callback needs additional data to generate the URL, it should be written to take a single argument. Some of the changes in this section aren't strictly necessary - they're included to demonstrate RTK Query's features and show some of the things you can do, so you can see how to use these features if you need them. We then use prepareHeaders to inject the authentication headers into every subsequent request. Normally you should stick with using the hooks, but here we're going to work with the user data using just the RTK Query core API so you can see how to use it. Any useMutation hooks with the same fixedCacheKey string will share results between each other Previously, we had a normalized lookup table for all of our notifications, and the UI selected those as a single sorted array. We've already seen that we can get the entire list of posts with useGetPostsQuery() and then transform it in the component, such as sorting inside of a useMemo. Setting Up RTK Query Our example application already works, but now it's time to migrate all of the async logic over to use RTK Query. In that case, you can make a sub-selection of fields for that object. It's worth stepping back for a minute to discuss what we just did further. If Component A calls useGetPostQuery (42), that data will be fetched. RTK Query is "designed to simplify common cases for loading data in a web application.". Hot reloading, CSB service workers and msw sometimes have trouble getting on the right page -- when that happens, just refresh in the CSB browser pane. Mutation endpoints should define either a query callback that constructs the URL (including any URL query params), or a queryFn callback that may do arbitrary async logic and return a result. Similar to our other mutations, we take some parameters and make a request to the server, with some data in the body of the request. getPosts and getUsers both expect the server to return an array, and getPost expects the individual Post object as the body. In this case, we always need user data, so we can skip unsubscribing. Mutating data (create/update/delete) and syncing the changes from the server with the cache. // Invalidates all queries that subscribe to this Post `id` only. For a small update like adding a reaction, we probably don't need to re-fetch the entire list of posts. Any useMutation hooks with the same fixedCacheKey string will share results between each other when any of the trigger functions are called. These examples are not meant to be what you base your application on, but exist to show very specific behaviors that you may not actually want or need in your application. In short: More information about these can be found here. There are several reasons for this: In comparison, we just normalized the response data for the getUsers endpoint, in that it's being stored as an {[id]: value} lookup table. Ideally, yes. RTK Query provides an option to share results across mutation hook instances using the fixedCacheKey option. You can look at the examples from this repository. It utilizes Redux under the hood and is built on top of Redux Tool k it (RTK). There is one caveat here. In June 2021, Redux Toolkit introduced a powerful tool for data fetching and caching called RTK Query. In this section, we'll continue migrating our example app to use RTK Query for the other data types, and see how to use some of its advanced features to simplify the codebase and improve user experience. You may have heard the term "normalized cache" in relation to other data fetching libraries like Apollo. We can implement the optimistic update by finding the specific Post entry in the getPosts cache, and "mutating" it to increment the reaction counter.

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