#REACT PRIVATE CACHE UPDATE#
#REACT PRIVATE CACHE PLUS#

Therefore, we see useMemo in action (the value of pow does not change when the component is re-rendered). For example, when handling authentication in React, the user session can be saved in the session storage until the browser gets closed.

You use private when you render your HTML on the server, and the rendered HTML contains user-specific or sensitive information. When closing the browser, you want the cache to become empty again, but when you refresh the browser tab, you want to keep the cache intact. The local cache (e.g., browser) can still cache private responses.

#REACT PRIVATE CACHE UPDATE#

First, we update randomNumber and we don’t affect the value of age. The difference between public and private is that a shared cache (e.g., CDN) can cache public responses but not private responses. The last two animations will illustrate what happens. In this example, the calculation of pow is not very complex, but you can imagine the benefits of doing this when our function is heavier and we have to re-render our component often. Also in important defaults section: Stale queries are refetched. If the query is currently being rendered via useQuery or related hooks, it will also be refetched in the background. When a query is invalidated with invalidateQueries, two things happen: It is marked as stale. Although it doesn’t really help much in terms of performance, its real benefit comes in the. From react-query docs - query invalidation. It allows us to protect ourselves against failing requests by always storing a previous version of the content we’re trying to retrieve. where each processor has a private L1 cache and at least one other level is shared. If our component re-renders and the value of age has not changed, useMemo will simply return the memoized result. This one might be the simplest, but yet an effective caching strategy. Apollo Client for React uses the React Context API under the hood to. The function is only executed when the value of age changes. It has a dependency on the age variable, which is why we pass it to the dependency argument of the useMemo call.

#REACT PRIVATE CACHE PLUS#

Our function returns a number that is the sum of age raised to the power of two, plus a random number. We memoize the result of a function call and store that result in a variable called pow.

This allows displaying the cached result first while fetching for the fresh data. By default, react-admin stores all the responses from the dataProvider in a local cache.

randomNumber (line 5): storing a random number with useState.Īnd finally, we use useMemo on line 7. React-admin comes with a built-in cache-first approach called optimistic rendering, and it supports caching both at the HTTP level and the application level.

age (line 4): storing a number representing an age with useState.

getRnd (line 2): a function that returns a random number in the range 0-10000.

React private cache