Memoize OverviewTab aggregation (extract pure overviewStats + useMemo)#5
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cybermejo merged 1 commit intoJun 17, 2026
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OverviewTab recomputed its full aggregation (sentiment distribution, tone counts, totals, averages, top-5) inline on every render, unlike the other tabs which useMemo. On large datasets any parent re-render redid the whole O(n) sweep. Extract the aggregation verbatim into a pure overviewStats(tweets) in lib/stats.js and call it via useMemo([tweets]) in the component. The JSX is unchanged. As a bonus the dashboard aggregation is now unit-testable without a DOM. Adds lib/stats.test.js (5 tests). Build green (identical CSS hash); 45 tests pass.
cybermejo
merged commit Jun 17, 2026
7f7ad6d
into
worktree-studio-modularize-and-test
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Summary
Memoizes the Overview tab's aggregation so it isn't recomputed on every render.
Why
OverviewTabcomputed its full aggregation (sentiment distribution, tone counts, engagement totals, averages, top-5 performers) inline in the function body — unlikeBrandsTab/CaptionStudio, whichuseMemo. Any parent re-render redid the whole O(n) sweep over all tweets.What changed
overviewStats(tweets)insrc/lib/stats.js.OverviewTabcalls it viauseMemo(() => overviewStats(tweets), [tweets]). The JSX is unchanged.Testing
Adds
src/lib/stats.test.js(5 tests: empty input, sentiment counts, engagement sums + averages, tone sorting, top-5 ranking). Build green with an identical CSS hash (markup unchanged); 45 tests pass.