The SWR 2.0 release candidate. This RC has one breaking change, a new option for mutation APIs, and some bug fixes & improvements.

Highlights & Breakings

A failed mutation will not cause useSWR's error to be updated:

const { error, mutate } = useSWR('/api/user', getUser)

return <button onClick={async () => {
  try {
    await mutate(updateUser)
  } catch (mutationError) {
    // `mutationError` will not cause `error` to be updated.
  }
}}>Update User</button>

In 2.0, with the example above, error will only be coming from getUser and will be shared across all useSWR('/api/user') hooks. And mutation errors (mutationError) will be coming from mutations like updateUser calls, they will be separated from fetcher errors.

There is also a new option throwOnError for useSWRMutation to disable the default throwing behavior of trigger:

const { trigger } = useSWRMutation('/api/user', updateUser)

try {
  await trigger()
} catch (err) {
  // ... it throws when failed to trigger the mutation so you can
  // easily change the flow here
}

const { trigger, error } = useSWRMutation('/api/user', updateUser, {
  throwOnError: false
})

// You don't need to try-catch here, you can instead handle errors
// on the component level in a declarative way
await trigger()

Read more about this change in #2182.

What's Changed

• chore: fix missing husky warning by @huozhi in https://github.com/vercel/swr/pull/2160
• fix: Remove downlevelIteration and traverse iterator manually by @huozhi in https://github.com/vercel/swr/pull/2181
• fix: re-render when returned data and fallbackData is the same and keepPreviousData is enabled by @koba04 in https://github.com/vercel/swr/pull/2169
• breaking: Change the error broadcasting behavior in mutations and add throwOnError option by @shuding in https://github.com/vercel/swr/pull/2182
• docs: Add JSDoc comments to useSWRMutation by @shuding in https://github.com/vercel/swr/pull/2183

Full Changelog: https://github.com/vercel/swr/compare/2.0.0-beta.7...2.0.0-rc.0