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@markerikson markerikson released this Feb 18, 2020 · 30 commits to master since this release

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 react-redux@7.2.0 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

Assets 2
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