![]() This tag should then have its "mode" attribute set to "Off". It could, however, be viewed by browsers running on the local server machine.ĭetails: To enable the details of this specific error message to be viewable on remote machines, please create a tag within a "web.config" configuration file located in the root directory of the current web application. The current custom error settings for this application prevent the details of the application error from being viewed remotely (for security reasons). Runtime Error Description: An application error occurred on the server. Runtime Error Server Error in '/' Application. data ? emptyUsersĮxport const selectUserById = createSelector ( select ( )Įxport const selectAllUsers = createSelector ( In this case, the users query has no params, so we don't pass anything to select()Įxport const selectUsersResult = apiSlice. To generate a selector for a specific query argument, call `select(theQueryArg)`. the query result object for a query with those parameters. Calling `lect(someArg)` generates a new selector that will return * Temporarily ignore adapter - we'll use this again shortlyĬonst usersAdapter = createEntityAdapter()Ĭonst initialState = usersAdapter.getInitialState() These specific tags look like from './api/apiSlice' Fortunately, RTK Query lets us define specific tags, which let us be more selective in invalidating data. We could add a 'Post' tag to both the getPost query and the editPost mutation, but that would force all the other individual posts to be refetched as well. That way, every time we add a new post, we force RTK Query to refetch the entire list of posts from the getQuery endpoint. We declared that the getPosts query endpoint provides a 'Post' tag, and that the addNewPost mutation endpoint invalidates that same 'Post' tag. We need a way to force a refetch of both the individual Post entry, and the entire list of posts.Įarlier, we saw how we can use "tags" to invalidate parts of our cached data. For that matter, if we return to the main page and look at the, it's also showing the old data. The is still using the cached Post entry that was fetched earlier. If we click "Save Post" while editing, it returns us to the, but it's still showing the old data without the edits. Our component can now save the edited post to the server, but we have a problem. So, RTK Query canceled the timer and kept using the same cached data instead of fetching it from the server.īy 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. But, the component mounted right away and subscribed to the same Post data with the same cache key. RTK Query immediately started a "remove this post data" timer. When we clicked on "Edit Post", the component was unmounted by the router, and the active subscription was removed due to unmounting. In this case, our mounted and requested that individual Post by ID. ![]() 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. 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. When the number of active subscriptions goes down to 0, RTK Query starts an internal timer. ![]() The two hook usages will return the exact same results, including fetched data and loading status flags. If Component B then mounts and also calls useGetPostQuery(42), it's the exact same data being requested. ![]() ![]() If Component A calls useGetPostQuery(42), that data will be fetched. Internally, RTK Query keeps a reference counter of active "subscriptions" to each endpoint + cache key combination. RTK Query allows multiple components to subscribe to the same data, and will ensure that each unique set of data is only fetched once. The UI switches over to show, but this time there's no network request for the individual post. Now click "Edit Post" inside the single post page. When you click on a "View Post" button, you should see a second request to /posts/:postId that returns that single post entry. You should see a GET request to /posts as we fetch the initial data. Open up your browser's DevTools, go to the Network tab, and refresh the main page. ![]()
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