@hazae41/xswr

npm i @hazae41/xswr

Node Package 📦 • Read the docs 📚 • Next.js Example 🪣 • Expo Example 🪣 • Comparison with other libs 🌐

Philosophy 🧠

xswr uses two new approaches compared to other data fetching libraries like swr or react-query:

1. Encapsulating key+fetcher+params in a single abstraction called schema.
2. Composing features with very simple hooks instead of having bloated configuration and unexpected behaviors.

Features 🔥

Current features

• 100% TypeScript and ESM
• Composition-based hooks
• Very easy learning curve
• No dependency except React
• Not over-engineered (hello react-query)
• No unexpected behaviour (hello swr)
• Backend agnostic fetching (REST, GraphQL, WebSocket)
• Storage agnostic caching (new Map(), LocalStorage, IndexedDB)
• Automatic refetching
• Dependent and conditional queries
• Request deduplication, cooldown, timeout, and expiration
• Page-based and cursor-based pagination
• Exponential backoff retry
• SSR & ISR support
• Optimistic mutations
• Cancellable requests
• Automatic cancellation
• Automatic garbage collection
• Per-query persistent storage
• Out of the box IndexedDB and LocalStorage
• Out of the box store normalization
• Super natural React Suspense
• React Native support

Upcoming features

• Transport agnostic streaming (ethers.js, WebSockets, Socket.io)
• Bidirectional scrolling

Installation 🔧

Just install @hazae41/xswr using your favorite package manager.

npm i @hazae41/xswr

Then, wrap your app in a CoreProvider component.

import { CoreProvider } from "@hazae41/xswr"

function MyWrapper() {
  return <CoreProvider>
    <MyAwesomeApp />
  </CoreProvider>
}

Your first mix 🧪

When using xswr and its composition-based hooks, you create a mix and only include the ingredients you want.

We'll do a request at /api/data using JSON, display it with a loading, and automatically refetch it.

Create a fetcher ⚡️

It will just take an url, fetch it, and return the data.

async function fetchAsJson<T>(url: string) {
  const res = await fetch(url)
  const data = await res.json() as T
  return { data }
}

Create a mix 🌪

Then create a mix using a query and some blocks.

function useHello() {
  const query = useQuery<Hello>(`/api/hello`, fetchAsJson)
  
  useFetch(query) // Fetch on mount and on url change
  useVisible(query) // Fetch when the page becomes visible
  useOnline(query) // Fetch when the browser becomes online

  return query
}

Use it in your components 🚀

function MyApp() {
  const { data, error } = useHello()

  if (error)
    return <MyError error={error} />
  if (!data)
    return <MyLoading />
  return <MyPage data={data} />
}

Advanced example 🗿

Last example was good, but here is the best way to use XSWR.

Making our fetcher cancellable ⚡️

Our fetcher was good, but this one can be aborted.

async function fetchAsJson<T>(url: string, more: FetcherMore<T>) {
  const { signal } = more

  const res = await fetch(url, { signal })

  if (!res.ok) {
    const error = new Error(await res.text())
    return { error }
  }

  const data = await res.json() as T
  return { data }
}

It also returns an error if the request failed.

Defining schemas 📐

Using schemas may seems boilerplate, but it will save you a lot of time later.

function getHelloSchema() {
  return getSchema<Hello>("/api/hello", fetchAsJson)
}

It allows you to reuse the same set of key+fetcher+params in multiple places, including imperative code.

Creating mixtures 🧪

The mixtures pattern allows you to reuse the same group of blocks.

function useAutoFetchMixture(query: Query) {
  useFetch(query)
  useVisible(query)
  useOnline(query)
}

Mixing it 🌪

Once you got a schema and a mixture, you just have to mix it.

function useHelloMix() {
  const query = useSchema(getHelloSchema, [])
  useAutoFetchMixture(query)
  return query
}

Use it in your app 🚀

function MyApp() {
  const { data, error } = useHelloMix()

  if (error)
    return <MyError error={error} />
  if (!data)
    return <MyLoading />
  return <MyPage data={data} />
}