While an app is in use, Relay will accumulate and cache (for some time) the data for the multiple queries that have been fetched throughout usage of our app. Often times, we'll want to be able to reuse and immediately render this data that is locally cached instead of waiting for a network request when fulfilling a query; this is what we'll cover in this section.
Some examples of when this might be useful are:
- Navigating between tabs in an app, where each app renders a query. If a tab has already been visited, re-visiting the tab should render it instantly, without having to wait for a network request to fetch the data that we've already fetched before.
- Navigating to a post that was previously rendered on a feed. If the post has already been rendered on a feed, navigating to the post's permalink page should render the post immediately, since all of the data for the post should already be cached.
- Even if rendering the post in the permalink page requires more data than rendering the post on a feed, we'd still like to reuse and immediately render as much of the post's data that we already have available locally, without blocking render for the entire post if only a small bit of data is missing.
Is this page useful?