HMR: debounce status indicator transitions to prevent flicker during bursts of changes#93229
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wbinnssmith wants to merge 1 commit intocanaryfrom
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HMR: debounce status indicator transitions to prevent flicker during bursts of changes#93229wbinnssmith wants to merge 1 commit intocanaryfrom
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…bursts of changes This adds a debounce to the _ui_ in development, reducing churn and flicker from the Next.js logo indicator's "Compiling" and "Rendering" messages. This is wholistic and covers any rapid changes in dev, usually caused by agents making a series of changes. This commit adds a useDebouncedValue hook and uses it to debounce status transitions in NextLogo, so rapid active->active alternations (e.g. Compiling→Rendering→Compiling) are smoothed into a single stable state for 300ms. Transitions to/from None remain immediate so: - Fast single builds that complete before the 400ms enterDelay still never show the pill. - The pill still appears promptly when a long build starts (no added latency on top of the existing enter delay). Changes: - use-debounced-value.ts: new generic trailing-edge debounce hook with an optional leading predicate to bypass the delay for specific transitions. - next-logo.tsx: apply the debounce to the computed status; derive shouldShowStatus from the debounced value so both pill mount-gating and label transitions are smoothed together. Test Plan: Ran a script that simulated an agent making hundreds of changes in rapid successions. Verified before this change, the indicator would flash between Compiling and Rendering rapidly. Now, it consistently stays on "Compiling" before the final render.
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Failing test suitesCommit: ad17296 | About building and testing Next.js
Expand output● mismatching prefetch › recovers when a navigation rewrites to a different route than the one that was prefetched |
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lukesandberg
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Apr 25, 2026
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This adds a debounce to the ui in development, reducing churn and flicker from the Next.js logo indicator's "Compiling" and "Rendering" messages. This is wholistic and covers any rapid changes in dev, usually caused by agents making a series of changes.
There's currently a debounce of 30ms coming from the subscription to changes in Turbopack itself, we could consider lengthening that as well.
This commit adds a useDebouncedValue hook and uses it to debounce status transitions in NextLogo, so rapid active->active alternations (e.g. Compiling→Rendering→Compiling) are smoothed into a single stable state for 300ms. Transitions to/from None remain immediate so:
Changes:
label transitions are smoothed together.
Test Plan: Ran a script that simulated an agent making hundreds of changes in rapid successions. Verified before this change, the indicator would flash between Compiling and Rendering rapidly. Now, it consistently stays on "Compiling" before the final render.