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react-redux v7.2.0 Release Notes

Release Date: 2020-02-18 // about 4 years ago

  • 🚀 This release fixes two bugs, an algorithmic problem with unsubscribing components and a memory leak with connect. It also has optimizations for production bundle size, and adds a couple small improvements to developer readability while debugging.

    🔄 Changes

    🐛 Bug Fixes

    connect in v7 is implemented using hooks, and the hooks usage captures numerous values from the surrounding scope. We received a PR informing us that the way we were capturing these values would likely result in a copy of the first version of its props being kept alive indefinitely.

    🛠 This memory leak has been fixed by extracting a custom hook that receives all the necessary values as arguments, so that they're not captured via closure.

    🚚 We also received a PR letting us know that the unsubscribe logic had a quadratic algorithm in it, as removing a subscriber would use an indexOf(listener) check to remove that callback. If there were a large number of subscribers, that line's runtime would increase rapidly, causing slowdowns.

    This algorithm has been replaced with tracking subscribers via a linked list, which drastically improves the runtime of this section of the code even with large numbers of subscribers.

    Thanks to @larrylin28 and @wurstbonbon for finding these bugs and submitting PRs to fix them!

    Bundle Size Improvements

    We've made a number of small tweaks to the codebase to improve the ability of bundlers to shake and minimize the final included size in a bundle. The net result is that [email protected] is smaller than 7.1.3, dropping 1.3K min and 0.6K min+gzip. (In fact, it's even smaller than the pre-hooks 7.0.0 when gzipped!)

    Thanks to @Andarist for doing most of the work on this!

    Debugging Improvements

    The ReactReduxContext instance now has a displayName set, so it should show up in the React DevTools as ReactRedux.Provider.

    Also, when an error is caught in useSelector and re-thrown, we now append the original stack trace.

    Thanks to @pieplu and @r3dm1ke for these!

    🔄 Changelog

    v7.1.3...v7.2.0