The Challenge

Tools for managing "global state" are plentiful these days, but most of these tools:

• Mistake server cache state for global state
• Force you to manage async data in a synchronous way
• Duplicate unnecessary network operations
• Use naive or over-engineered caching strategies
• Are too basic to handle large-scale apps or
• Are too complex or built for highly-opinionated systems like Redux, GraphQL, [insert proprietary tools], etc.
• Do not provide tools for server mutations
• Either do not provide easy access to the cache or do, but expose overpowered foot-gun APIs to the developer

The Solution

React Virtual exports a set of hooks that address these issues. Out of the box, React Virtual:

• Separates your server cache state from your global state
• Provides async aware APIs for reading and updating server state/cache
• Dedupes both async and sync requests to async resources
• Automatically caches data, invalidates and refetches stale data, and manages garbage collection of unused data
• Scales easily as your application grows
• Is based solely on Promises, making it highly unopinionated and interoperable with any data fetching strategy including REST, GraphQL and other transactional APIs
• Provides an integrated promise-based mutation API
• Opt-in Manual or Advance cache management

Zeit's SWR is a great library, and is very similar in spirit and implementation to React Virtual with a few notable differences:

• Automatic Cache Garbage Collection - React Virtual handles automatic cache purging for inactive queries and garbage collection. This can mean a much smaller memory footprint for apps that consume a lot of data or data that is changing often in a single session
• No Default Data Fetcher Function - React Virtual does not ship with a default fetcher (but can easily be wrapped inside of a custom hook to achieve the same functionality)
• useMutation - A dedicated hook for handling generic lifecycles around triggering mutations and handling their side-effects in applications. SWR does not ship with anything similar, and you may find yourself reimplementing most if not all of useMutation's functionality in user-land. With this hook, you can extend the lifecycle of your mutations to reliably handle successful refetching strategies, failure rollbacks and error handling.
• Prefetching - React Virtual ships with 1st class prefetching utilities which not only come in handy with non-suspenseful apps but also make fetch-as-you-render patterns possible with React Virtual. SWR does not come with similar utilities and relies on <link rel='preload'> and/or manually fetching and updating the query cache
• Query cancellation integration is baked into React Virtual. You can easily use this to wire up request cancellation in most popular fetching libraries, including but not limited to fetch and axios.
• Query Key Generation - React Virtual uses query key generation, query variables, and implicit query grouping. The query key and variables that are passed to a query are less URL/Query-based by nature and much more flexible. All items supplied to the query key array are used to compute the unique key for a query (using a stable and deterministic sorting/hashing implementation). This means you can spend less time thinking about precise key matching, but more importantly, allows you to use partial query-key matching when refetching, updating, or removing queries in mass eg. you can refetch every query that starts with a todos in its key, regardless of variables, or you can target specific queries with (or without) variables, and even use functional filtering to select queries in most places. This architecture is much more robust and forgiving especially for larger apps.