swr 1.2.0

on Node.js Yarn

Highlights of This Release

Optimistic Updates with Auto Error Rollback

There are now some new options in mutate:

mutate(patchUser(user), {
  optimisticData: user,
  populateCache: true,
  rollbackOnError: true,
  revalidate: true,
})

Here the cache will be immediately updated to user, the “optimistic value”. And then a request (remote mutation) is started via patchUser(user) and the response will be written to the cache. If that request fails, the original result will be rolled back safely so the optimistic value will be gone. And after all those finish, a revalidation will start to fetch the latest value.

This is extremely helpful for building the optimistic UI pattern.

You can do the same for the global mutate, just remember to pass the key. Also, the current mutate APIs stay unchanged so mutate(data, false) works the same.

Here's an example: https://codesandbox.io/s/swr-basic-forked-k5hps.

.mjs Support

SWR now has .mjs exported for bundlers that prefer this format.

This doesn’t break environments that don’t support .mjs. An alternative .esm.js and CJS bundle are also published.

You can read more about ES modules here.

What's Changed

• feat: Optimistic mutation with error rollback by @shuding in #1745
• fix: Required return type when mutating by @RKatarine in #1772
• fix: use the latest reference of fetcher with suspense mode by @koba04 in #1803
• test: add delay for flaky focus test by @huozhi in #1762
• test: remove flaky focus test case by @huozhi in #1793
• test: use @swc/jest by @huozhi in #1790
• chore: Ignore coverage report by @shuding in #1744
• chore: Merge mutation states by @shuding in #1748
• chore: Rename CONCURRENT_REQUESTS to FETCH by @shuding in #1749
• chore: Merge extra request states in cache by @shuding in #1752
• chore: support mjs exports by @huozhi in #1760
• chore: remove useless react-native field by @huozhi in #1761
• chore: comment helper by @huozhi in #1757
• chore: display name in devtool by @huozhi in #1779
• chore: simplify example development by @huozhi in #1787
• chore: build: improve watch commands by @huozhi in #1788
• chore: Update examples and dependencies by @shuding in #1789
• chore: zeit -> vercel by @huozhi in #1791
• chore: Clean up configurations by @shuding in #1792
• chore: move community health files to .github dir by @huozhi in #1794
• chore: Add link to security email directly by @huozhi in #1795

New Contributors

• @RKatarine made their first contribution in #1772

Full Changelog: 1.1.2...1.2.0