Sourced from preact's releases.

Preact X - Virtuous DOM and the Fragments of Suspense

tl;dr: Preact X is the next major version of Preact fully packed with features like Fragments, Hooks, componentDidCatch, Test-Utils, Debug-Warnings, many compatibility fixes and so much more 🎉

It's finally happening! After months of hard work we've crossed the finish line and are over the moon with excitement to finally mark Preact X as stable. We'd like to thank everybody who tested it and submitted bug reports.

We originally planned to release a sort-of migration release as version 9 with just the breaking changes from X, but that got canned because many users reported that the upgrade process was easy enough and didn't warrant a long migration period in-between. In fact we got many reports that the upgrade could be done in under an hour, despite some of the breaking changes in X, making the need for a migration release even less desirable.

What's new?

Preact X ships with several major features and we combined them all in a single document on our site. If you're upgrading an existing Preact 8.x project, we got you covered with a detailed upgrade guide.

To give a quick summary of the new features:

• Fragments
• componentDidCatch
• preact/hooks addon
• preact/test-utils addon
• createContext API
• compat moved to core
• Plethora of compatibility fixes
• Many new warnings in preact/debug
• Same 3 kB size as Preact 8

Again, we highly recommend checking out our new site and specifically the what's new section.

Changes since RC 4

Bug Fixes

• Rewrite shouldComponentUpdate handling to take more edge cases into account (#1931, thanks @​JoviDeCroock)
• Fix UNSAFE_* lifecycles being overwritten in compat (#1946, thanks @​marvinhagemeister)
• Fix PureComponent rerendering when __source changes (#1950, thanks @​JoviDeCroock)
• Fix default argument in useState not applied in rare cases (#1948, thanks @​JoviDeCroock)
• Change .forceUpdate() to participate in the update queue (#1939, thanks @​developit)
• Fix vnode._children should keep their type as array when diffing (#1924, thanks @​cristianbote)
• Allow numeric CSS values to be 0 (e.g. opacity) (#1927, thanks @​JoviDeCroock)
• Fix unnecessary rerender on equal contexts (#1925, thanks @​JoviDeCroock)

Typings

• Add disableRemotePlayback to HTML Attributes (#1955, thanks @​JoviDeCroock)
• Add volume to HTML Attributes (#1938, thanks @​jessicabyrne)

Maintenance

• Prevent mangling of __source and __self (#1958, thanks @​JoviDeCroock)

... (truncated)

• 9ddc04e Release 10.0.0 (aka X) (#1960)
• 620df71 (chore) - fix some typing issues (#1955)
• f042d6b (chore) - prevent mangling of __source and __self (#1958)
• 870cf60 Fix UNSAFE_* lifecycles being overwritten (#1946)
• 0bd9f56 Golf -1 B
• ea095da Fix UNSAFE_* lifecycles being overwritten
• 07962d0 Merge pull request #1950 from preactjs/fix/pureComponent
• de388d2 (fix) - make shallowDiffers take __source in account
• 4aa291e (fix) - defaulting arguments in useState (#1948)
• eaafa71 Change .forceUpdate() to participate in the update queue (#1939)
• Additional commits viewable in compare view

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