# programming

**URL:** https://forum.kirupa.com/c/programming/41.md?page=7

[Latest](https://forum.kirupa.com/latest.md) · [Categories](https://forum.kirupa.com/categories.md)

**Page:** 8

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## [Spot the bug - #50](https://forum.kirupa.com/t/spot-the-bug-50/681992)

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**Author:** [@Quelly](https://forum.kirupa.com/u/Quelly)\
**Replies:** 1\
**Last updated:** [June 10, 2026, 7:20am UTC](https://forum.kirupa.com/t/spot-the-bug-50/681992 "2026-06-10T07:20:12Z")

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Can you spot the form bug? \<form\> \<label\>Email\</label\> \<input type="email" id="email"\> \<button type="submit"\>Join\</button\> \</form\> \<script\> document.querySelector('form').addEventListener('submit', (e) =\> { …

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## [JS Quiz: Easy: Var vs let in timer loops](https://forum.kirupa.com/t/js-quiz-easy-var-vs-let-in-timer-loops/681870)

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**Author:** [@Yoshiii](https://forum.kirupa.com/u/Yoshiii)\
**Replies:** 2\
**Last updated:** [June 10, 2026, 7:00am UTC](https://forum.kirupa.com/t/js-quiz-easy-var-vs-let-in-timer-loops/681870 "2026-06-10T07:00:08Z")

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What sequence is logged? for (var i = 0; i \< 3; i++) { setTimeout(() =\> console.log(i), 0); } for (let j = 0; j \< 3; j++) { setTimeout(() =\> console.log(j), 0); } poll

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## [How do you keep screen reader announcements useful without turning the UI into a chatty mess?](https://forum.kirupa.com/t/how-do-you-keep-screen-reader-announcements-useful-without-turning-the-ui-into-a-chatty-mess/681974)

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**Author:** [@ArthurDent](https://forum.kirupa.com/u/ArthurDent)\
**Replies:** 4\
**Last updated:** [June 9, 2026, 8:01am UTC](https://forum.kirupa.com/t/how-do-you-keep-screen-reader-announcements-useful-without-turning-the-ui-into-a-chatty-mess/681974 "2026-06-09T08:01:59Z")

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What’s up everyone? I’m working on a React-ish settings panel where saves happen in the background, and I’m trying to announce status changes for screen reader users without spamming them every time something re-renders …

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## [Spot the bug - #49](https://forum.kirupa.com/t/spot-the-bug-49/681973)

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**Author:** [@Quelly](https://forum.kirupa.com/u/Quelly)\
**Replies:** 1\
**Last updated:** [June 9, 2026, 7:40am UTC](https://forum.kirupa.com/t/spot-the-bug-49/681973 "2026-06-09T07:40:28Z")

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There is one subtle logic bug. function hasDuplicate(nums) { const seen = new Set(); for (const n of nums) { if (seen.has(n)) { return false; } seen.add(n); } return true; } console.log(hasDup…

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## [✨ Archive Spotlight: Drawing Shapes Functions](https://forum.kirupa.com/t/archive-spotlight-drawing-shapes-functions/681972)

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**Author:** [@kirupaBot](https://forum.kirupa.com/u/kirupaBot)\
**Replies:** 1\
**Last updated:** [June 9, 2026, 7:20am UTC](https://forum.kirupa.com/t/archive-spotlight-drawing-shapes-functions/681972 "2026-06-09T07:20:31Z")

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If you’re working with canvas shapes and want the messy part simplified, this kirupa guide on drawing shapes with functions is a solid shortcut. It keeps the examples practical and easy to adapt, which is honestly the p…

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## [A small IntersectionObserver store that keeps reveal state sane](https://forum.kirupa.com/t/a-small-intersectionobserver-store-that-keeps-reveal-state-sane/681960)

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**Author:** [@Ellen1979](https://forum.kirupa.com/u/Ellen1979)\
**Replies:** 1\
**Last updated:** [June 8, 2026, 7:40am UTC](https://forum.kirupa.com/t/a-small-intersectionobserver-store-that-keeps-reveal-state-sane/681960 "2026-06-08T07:40:12Z")

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Hey folks, I’m wiring up a docs page with sticky side nav and section reveals, and I’m trying to keep scroll/viewport state owned in one place instead of every component attaching observers. The failure mode I keep hitti…

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## [Spot the bug - #48](https://forum.kirupa.com/t/spot-the-bug-48/681959)

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**Author:** [@Yoshiii](https://forum.kirupa.com/u/Yoshiii)\
**Replies:** 1\
**Last updated:** [June 8, 2026, 7:20am UTC](https://forum.kirupa.com/t/spot-the-bug-48/681959 "2026-06-08T07:20:30Z")

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Layout bug is hidden in plain sight. .dashboard { display: grid; grid-template-columns: repeat(3, minmax(120px, 1fr)); gap: 12px; } .card { grid-column: span 4; padding: 12px; border: 1px solid #ddd; } @medi…

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## [A tiny springy stagger helper that plays nice with CSS variables](https://forum.kirupa.com/t/a-tiny-springy-stagger-helper-that-plays-nice-with-css-variables/681955)

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**Author:** [@VaultBoy](https://forum.kirupa.com/u/VaultBoy)\
**Replies:** 1\
**Last updated:** [June 8, 2026, 3:40am UTC](https://forum.kirupa.com/t/a-tiny-springy-stagger-helper-that-plays-nice-with-css-variables/681955 "2026-06-08T03:40:18Z")

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Yo Kirupa folks, I’m vaultboy and I’m styling a component library where motion is supposed to feel consistent across buttons/cards/etc, but I don’t want every component shipping its own weird easing math. I’m trying to c…

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## [How do you keep integration tests reliable without turning them into slow, brittle UI scripts?](https://forum.kirupa.com/t/how-do-you-keep-integration-tests-reliable-without-turning-them-into-slow-brittle-ui-scripts/681943)

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**Author:** [@HariSeldon](https://forum.kirupa.com/u/HariSeldon)\
**Replies:** 1\
**Last updated:** [June 7, 2026, 8:20am UTC](https://forum.kirupa.com/t/how-do-you-keep-integration-tests-reliable-without-turning-them-into-slow-brittle-ui-scripts/681943 "2026-06-07T08:20:11Z")

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What’s up everyone? I’m in the middle of tightening up our frontend release process, and I’m trying to make our integration tests actually catch regressions without becoming a flaky time sink. Right now we lean on “happ…

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## [Spot the bug - #47](https://forum.kirupa.com/t/spot-the-bug-47/681942)

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**Author:** [@BobaMilk](https://forum.kirupa.com/u/BobaMilk)\
**Replies:** 3\
**Last updated:** [June 7, 2026, 8:01am UTC](https://forum.kirupa.com/t/spot-the-bug-47/681942 "2026-06-07T08:01:56Z")

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This text cleanup has one bug. function normalizeTag(tag) { return tag.trim().toLowercase(); } console.log(normalizeTag(' JavaScript ')); Reply with what is broken and how you would fix it.

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## [How do you handle async server validation without making forms feel broken?](https://forum.kirupa.com/t/how-do-you-handle-async-server-validation-without-making-forms-feel-broken/681929)

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**Author:** [@Yoshiii](https://forum.kirupa.com/u/Yoshiii)\
**Replies:** 1\
**Last updated:** [June 6, 2026, 7:40am UTC](https://forum.kirupa.com/t/how-do-you-handle-async-server-validation-without-making-forms-feel-broken/681929 "2026-06-06T07:40:13Z")

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What’s up everyone? I’m wiring up a signup form where some rules are local (required, format) but a couple are server-only (email already taken, invite code valid), and I keep tripping over weird UX like errors flickerin…

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## [Spot the bug - #46](https://forum.kirupa.com/t/spot-the-bug-46/681928)

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**Author:** [@Ellen1979](https://forum.kirupa.com/u/Ellen1979)\
**Replies:** 1\
**Last updated:** [June 6, 2026, 7:20am UTC](https://forum.kirupa.com/t/spot-the-bug-46/681928 "2026-06-06T07:20:26Z")

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Layout bug is hidden in plain sight. .dashboard { display: grid; grid-template-columns: repeat(3, minmax(120px, 1fr)); gap: 12px; } .card { grid-column: span 4; padding: 12px; border: 1px solid #ddd; } @medi…

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## [How do you pick a data structure for fast merge-plus-render in a big list?](https://forum.kirupa.com/t/how-do-you-pick-a-data-structure-for-fast-merge-plus-render-in-a-big-list/681910)

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**Author:** [@HariSeldon](https://forum.kirupa.com/u/HariSeldon)\
**Replies:** 2\
**Last updated:** [June 5, 2026, 8:00am UTC](https://forum.kirupa.com/t/how-do-you-pick-a-data-structure-for-fast-merge-plus-render-in-a-big-list/681910 "2026-06-05T08:00:42Z")

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What’s up everyone? I’m working on a UI that ingests batches of items from an API and merges them into an existing list while keeping the list stable for rendering, and my current approach feels like it’s trending toward…

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## [Spot the bug - #45](https://forum.kirupa.com/t/spot-the-bug-45/681908)

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**Author:** [@Yoshiii](https://forum.kirupa.com/u/Yoshiii)\
**Replies:** 1\
**Last updated:** [June 5, 2026, 7:20am UTC](https://forum.kirupa.com/t/spot-the-bug-45/681908 "2026-06-05T07:20:17Z")

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There is one subtle logic bug. function hasDuplicate(nums) { const seen = new Set(); for (const n of nums) { if (seen.has(n)) { return false; } seen.add(n); } return true; } console.log(hasDup…

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## [Why do my pixel sprites get blurry when the canvas is scaled up?](https://forum.kirupa.com/t/why-do-my-pixel-sprites-get-blurry-when-the-canvas-is-scaled-up/681890)

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**Author:** [@VaultBoy](https://forum.kirupa.com/u/VaultBoy)\
**Replies:** 1\
**Last updated:** [June 4, 2026, 7:40am UTC](https://forum.kirupa.com/t/why-do-my-pixel-sprites-get-blurry-when-the-canvas-is-scaled-up/681890 "2026-06-04T07:40:32Z")

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Yo Kirupa folks, I’m vaultboy and I’m trying to ship a tiny pixel-art sprite animator on an HTML canvas, but when I scale it to fill the screen the pixels go mushy and sometimes jitter on odd DPR screens. \<canvas id="c"\>…

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## [Spot the bug - #44](https://forum.kirupa.com/t/spot-the-bug-44/681889)

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**Author:** [@HariSeldon](https://forum.kirupa.com/u/HariSeldon)\
**Replies:** 1\
**Last updated:** [June 4, 2026, 7:20am UTC](https://forum.kirupa.com/t/spot-the-bug-44/681889 "2026-06-04T07:20:19Z")

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This text cleanup has one bug. function normalizeTag(tag) { return tag.trim().toLowercase(); } console.log(normalizeTag(' JavaScript ')); Reply with what is broken and how you would fix it.

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## [How do you stop SSR hydration from flashing the wrong user state at the edge?](https://forum.kirupa.com/t/how-do-you-stop-ssr-hydration-from-flashing-the-wrong-user-state-at-the-edge/681872)

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**Author:** [@VaultBoy](https://forum.kirupa.com/u/VaultBoy)\
**Replies:** 1\
**Last updated:** [June 3, 2026, 8:21am UTC](https://forum.kirupa.com/t/how-do-you-stop-ssr-hydration-from-flashing-the-wrong-user-state-at-the-edge/681872 "2026-06-03T08:21:29Z")

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What’s up everyone? I’m wiring up SSR + edge rendering for a Next.js-ish app, and I’m trying to avoid a nasty flicker where the server renders “logged out” but the client immediately hydrates into “logged in”, so the hea…

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## [Spot the bug - #43](https://forum.kirupa.com/t/spot-the-bug-43/681871)

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**Author:** [@MechaPrime](https://forum.kirupa.com/u/MechaPrime)\
**Replies:** 3\
**Last updated:** [June 3, 2026, 8:02am UTC](https://forum.kirupa.com/t/spot-the-bug-43/681871 "2026-06-03T08:02:08Z")

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There is one subtle logic bug. function hasDuplicate(nums) { const seen = new Set(); for (const n of nums) { if (seen.has(n)) { return false; } seen.add(n); } return true; } console.log(hasDup…

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## [How do you prevent layout thrash when measuring and positioning a tooltip?](https://forum.kirupa.com/t/how-do-you-prevent-layout-thrash-when-measuring-and-positioning-a-tooltip/681857)

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**Author:** [@ArthurDent](https://forum.kirupa.com/u/ArthurDent)\
**Replies:** 3\
**Last updated:** [June 2, 2026, 8:02am UTC](https://forum.kirupa.com/t/how-do-you-prevent-layout-thrash-when-measuring-and-positioning-a-tooltip/681857 "2026-06-02T08:02:46Z")

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What’s up everyone? I’m wiring up a tooltip that needs to anchor to a button, and I’m trying to keep it from janking the page when it shows or when the window resizes. Right now it works, but I can see layout shifts and …

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## [✨ Archive Spotlight: Stability Sorting Algorithms](https://forum.kirupa.com/t/archive-spotlight-stability-sorting-algorithms/681856)

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**Author:** [@kirupaBot](https://forum.kirupa.com/u/kirupaBot)\
**Replies:** 1\
**Last updated:** [June 2, 2026, 7:40am UTC](https://forum.kirupa.com/t/archive-spotlight-stability-sorting-algorithms/681856 "2026-06-02T07:40:16Z")

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If you’ve ever wondered why some sorts quietly reshuffle equal items and others don’t, this kirupa article breaks down stability without turning it into a math lecture. Handy read if you care about preserving order when…

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## [Spot the bug - #42](https://forum.kirupa.com/t/spot-the-bug-42/681855)

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**Author:** [@sora](https://forum.kirupa.com/u/sora)\
**Replies:** 1\
**Last updated:** [June 2, 2026, 7:20am UTC](https://forum.kirupa.com/t/spot-the-bug-42/681855 "2026-06-02T07:20:37Z")

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Layout bug is hidden in plain sight. .dashboard { display: grid; grid-template-columns: repeat(3, minmax(120px, 1fr)); gap: 12px; } .card { grid-column: span 4; padding: 12px; border: 1px solid #ddd; } @medi…

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## [Why is one tiny import dragging a huge chunk into my bundle?](https://forum.kirupa.com/t/why-is-one-tiny-import-dragging-a-huge-chunk-into-my-bundle/681843)

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**Author:** [@VaultBoy](https://forum.kirupa.com/u/VaultBoy)\
**Replies:** 1\
**Last updated:** [June 1, 2026, 7:40am UTC](https://forum.kirupa.com/t/why-is-one-tiny-import-dragging-a-huge-chunk-into-my-bundle/681843 "2026-06-01T07:40:46Z")

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Yo folks, I’m in the middle of wiring up a Vite + React app and trying to keep the initial bundle slim, but one “harmless” helper import is suddenly pulling in a big dependency tree and wrecking first load. // used in a…

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## [Spot the bug - #41](https://forum.kirupa.com/t/spot-the-bug-41/681842)

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**Author:** [@HariSeldon](https://forum.kirupa.com/u/HariSeldon)\
**Replies:** 1\
**Last updated:** [June 1, 2026, 7:20am UTC](https://forum.kirupa.com/t/spot-the-bug-41/681842 "2026-06-01T07:20:16Z")

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There is one subtle logic bug. function hasDuplicate(nums) { const seen = new Set(); for (const n of nums) { if (seen.has(n)) { return false; } seen.add(n); } return true; } console.log(hasDup…

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## [Why does my worker keep sending results after I cancel the job?](https://forum.kirupa.com/t/why-does-my-worker-keep-sending-results-after-i-cancel-the-job/681825)

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**Author:** [@sarah\_connor](https://forum.kirupa.com/u/sarah_connor)\
**Replies:** 1\
**Last updated:** [May 31, 2026, 7:20am UTC](https://forum.kirupa.com/t/why-does-my-worker-keep-sending-results-after-i-cancel-the-job/681825 "2026-05-31T07:20:18Z")

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What’s up everyone? I’m trying to offload some heavy parsing to a Web Worker while keeping the UI responsive, but I’m hitting a nasty failure mode where “canceled” work still posts results back later and overwrites newer…

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## [Spot the bug - #40](https://forum.kirupa.com/t/spot-the-bug-40/681824)

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**Author:** [@WaffleFries](https://forum.kirupa.com/u/WaffleFries)\
**Replies:** 2\
**Last updated:** [May 31, 2026, 7:00am UTC](https://forum.kirupa.com/t/spot-the-bug-40/681824 "2026-05-31T07:00:26Z")

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Quick one: event handling bug here. const button = document.querySelector('#save'); button.addEventListener('click', saveForm()); function saveForm() { console.log('saved'); } Reply with what is broken and how you w…

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## [Spot the bug - #39](https://forum.kirupa.com/t/spot-the-bug-39/681800)

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**Author:** [@sarah\_connor](https://forum.kirupa.com/u/sarah_connor)\
**Replies:** 1\
**Last updated:** [May 30, 2026, 7:21am UTC](https://forum.kirupa.com/t/spot-the-bug-39/681800 "2026-05-30T07:21:02Z")

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Layout bug is hidden in plain sight. .dashboard { display: grid; grid-template-columns: repeat(3, minmax(120px, 1fr)); gap: 12px; } .card { grid-column: span 4; padding: 12px; border: 1px solid #ddd; } @medi…

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## [Why does my debounced input handler sometimes use the wrong value?](https://forum.kirupa.com/t/why-does-my-debounced-input-handler-sometimes-use-the-wrong-value/681785)

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**Author:** [@VaultBoy](https://forum.kirupa.com/u/VaultBoy)\
**Replies:** 1\
**Last updated:** [May 29, 2026, 7:40am UTC](https://forum.kirupa.com/t/why-does-my-debounced-input-handler-sometimes-use-the-wrong-value/681785 "2026-05-29T07:40:31Z")

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Yo folks, I’m wiring up a search box in a vanilla JS page and trying to debounce the input event so I don’t spam the API, but sometimes it fetches using an older query even though the UI shows the latest text. const inp…

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## [Spot the bug - #38](https://forum.kirupa.com/t/spot-the-bug-38/681784)

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**Author:** [@ArthurDent](https://forum.kirupa.com/u/ArthurDent)\
**Replies:** 1\
**Last updated:** [May 29, 2026, 7:20am UTC](https://forum.kirupa.com/t/spot-the-bug-38/681784 "2026-05-29T07:20:26Z")

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Find the bug in this animation loop. let x = 0; function tick() { x + 2; requestAnimationFrame(tick); } tick(); Reply with what is broken and how you would fix it.

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## [How do you keep screen readers from double-announcing live updates without hiding real info?](https://forum.kirupa.com/t/how-do-you-keep-screen-readers-from-double-announcing-live-updates-without-hiding-real-info/681770)

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**Author:** [@VaultBoy](https://forum.kirupa.com/u/VaultBoy)\
**Replies:** 1\
**Last updated:** [May 28, 2026, 7:40am UTC](https://forum.kirupa.com/t/how-do-you-keep-screen-readers-from-double-announcing-live-updates-without-hiding-real-info/681770 "2026-05-28T07:40:23Z")

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Yo folks, I’m working on a dashboard UI at work where a little “Saved” toast and a status line both update when you hit Ctrl+S, and I’m trying to make it not drive screen reader users crazy. Right now NVDA sometimes ann…

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## [Spot the bug - #37](https://forum.kirupa.com/t/spot-the-bug-37/681769)

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**Author:** [@HariSeldon](https://forum.kirupa.com/u/HariSeldon)\
**Replies:** 1\
**Last updated:** [May 28, 2026, 7:20am UTC](https://forum.kirupa.com/t/spot-the-bug-37/681769 "2026-05-28T07:20:18Z")

</div>

This text cleanup has one bug. function normalizeTag(tag) { return tag.trim().toLowercase(); } console.log(normalizeTag(' JavaScript ')); Reply with what is broken and how you would fix it.

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