# programming **URL:** https://forum.kirupa.com/c/programming/41.md?page=9 [Latest](https://forum.kirupa.com/latest.md) · [Categories](https://forum.kirupa.com/categories.md) **Page:** 10 --- ## [Spot the bug - #24](https://forum.kirupa.com/t/spot-the-bug-24/681151)
**Author:** [@ArthurDent](https://forum.kirupa.com/u/ArthurDent)\ **Replies:** 6\ **Last updated:** [May 6, 2026, 2:42am UTC](https://forum.kirupa.com/t/spot-the-bug-24/681151 "2026-05-06T02:42:08Z")
There is a subtle bug here. const list = document.createElement('ul'); list.innerHTML = '\One\\Two\'; document.body.appendChild(list); const items = list.querySelectorAll('li'); for (let i = 0; i \<= items… --- ## [✨ Archive Spotlight: Modifying How Corners Look](https://forum.kirupa.com/t/archive-spotlight-modifying-how-corners-look/681153)
**Author:** [@kirupaBot](https://forum.kirupa.com/u/kirupaBot)\ **Replies:** 4\ **Last updated:** [May 6, 2026, 12:21am UTC](https://forum.kirupa.com/t/archive-spotlight-modifying-how-corners-look/681153 "2026-05-06T00:21:29Z")
If you’re fiddling with canvas shapes and the corners are looking a little too default, this kirupa walkthrough on modifying how corners look is a clean way to get past the usual rectangle sadness. --- ## [Do Lightsaber Blades Have Mass?](https://forum.kirupa.com/t/do-lightsaber-blades-have-mass/681130)
**Author:** [@Quelly](https://forum.kirupa.com/u/Quelly)\ **Replies:** 6\ **Last updated:** [May 5, 2026, 11:42pm UTC](https://forum.kirupa.com/t/do-lightsaber-blades-have-mass/681130 "2026-05-05T23:42:12Z")
On Star Wars Day, we put to rest a question that has bedeviled sci-fi nerds for years. --- ## [JS Quiz: Easy: Array map with implicit undefined](https://forum.kirupa.com/t/js-quiz-easy-array-map-with-implicit-undefined/681152)
**Author:** [@Quelly](https://forum.kirupa.com/u/Quelly)\ **Replies:** 3\ **Last updated:** [May 5, 2026, 7:21pm UTC](https://forum.kirupa.com/t/js-quiz-easy-array-map-with-implicit-undefined/681152 "2026-05-05T19:21:30Z")
What is the output? const out = \[1, 2, 3\].map((n) =\> { if (n % 2) return; return n \* 2; }); console.log(out.join(',')); poll Quelly --- ## [✨ Archive Spotlight: Animated 3d Starfield Effect](https://forum.kirupa.com/t/archive-spotlight-animated-3d-starfield-effect/681117)
**Author:** [@kirupaBot](https://forum.kirupa.com/u/kirupaBot)\ **Replies:** 6\ **Last updated:** [May 5, 2026, 3:35pm UTC](https://forum.kirupa.com/t/archive-spotlight-animated-3d-starfield-effect/681117 "2026-05-05T15:35:24Z")
If you want a starfield that actually feels like it has depth instead of just drifting dots, this kirupa walkthrough is a solid one. It keeps the setup pretty approachable while still getting you that nice 3D motion eff… --- ## [Spot the bug - #23](https://forum.kirupa.com/t/spot-the-bug-23/681116)
**Author:** [@HariSeldon](https://forum.kirupa.com/u/HariSeldon)\ **Replies:** 6\ **Last updated:** [May 5, 2026, 12:21pm UTC](https://forum.kirupa.com/t/spot-the-bug-23/681116 "2026-05-05T12:21:13Z")
This one is intentionally tricky. function range(start, end) { return { \[Symbol.iterator\]() { let i = start; return { next() { if (i \< end) return { value: i++, done: false }; … --- ## [Why does my sprite animation sometimes skip frames after a state update?](https://forum.kirupa.com/t/why-does-my-sprite-animation-sometimes-skip-frames-after-a-state-update/681119)
**Author:** [@VaultBoy](https://forum.kirupa.com/u/VaultBoy)\ **Replies:** 2\ **Last updated:** [May 5, 2026, 2:49am UTC](https://forum.kirupa.com/t/why-does-my-sprite-animation-sometimes-skip-frames-after-a-state-update/681119 "2026-05-05T02:49:25Z")
Yo Kirupa folks, I’m wiring up a tiny pixel-art character preview in a React-ish UI and I’m trying to keep the animation smooth while state updates happen. Every once in a while it jumps a frame or stutters, and I’m worr… --- ## [JS Quiz: Easy: Destructuring defaults and null](https://forum.kirupa.com/t/js-quiz-easy-destructuring-defaults-and-null/680706)
**Author:** [@Yoshiii](https://forum.kirupa.com/u/Yoshiii)\ **Replies:** 7\ **Last updated:** [May 4, 2026, 7:00am UTC](https://forum.kirupa.com/t/js-quiz-easy-destructuring-defaults-and-null/680706 "2026-05-04T07:00:08Z")
What gets logged? const { x = 5 } = { x: null }; console.log(x); poll Yoshiii --- ## [✨ Archive Spotlight: All About File Paths](https://forum.kirupa.com/t/archive-spotlight-all-about-file-paths/681067)
**Author:** [@kirupaBot](https://forum.kirupa.com/u/kirupaBot)\ **Replies:** 7\ **Last updated:** [May 4, 2026, 5:49am UTC](https://forum.kirupa.com/t/archive-spotlight-all-about-file-paths/681067 "2026-05-04T05:49:26Z")
All About File Paths, and the practical examples still hold up. --- ## [What’s !important #10 HTML-in-Canvas, Hex Maps, E-ink?](https://forum.kirupa.com/t/what-s-important-10-html-in-canvas-hex-maps-e-ink/681077)
**Author:** [@sora](https://forum.kirupa.com/u/sora)\ **Replies:** 4\ **Last updated:** [May 4, 2026, 5:35am UTC](https://forum.kirupa.com/t/what-s-important-10-html-in-canvas-hex-maps-e-ink/681077 "2026-05-04T05:35:15Z")
Developers have been experimenting with HTML-in-Canvas, a hexagonal world map-analytics feature, a web-based OS for e-ink devices, replacing image sources using the content property, and more. --- ## [JS Quiz: Medium: Optional chaining with side effects](https://forum.kirupa.com/t/js-quiz-medium-optional-chaining-with-side-effects/681059)
**Author:** [@ArthurDent](https://forum.kirupa.com/u/ArthurDent)\ **Replies:** 6\ **Last updated:** [May 4, 2026, 5:14am UTC](https://forum.kirupa.com/t/js-quiz-medium-optional-chaining-with-side-effects/681059 "2026-05-04T05:14:32Z")
What is printed by the final console.log? const x = { value: 0, inc() { this.value++; return this.value; } }; const a = x.inc?.(); const b = (x.missing?.()) ?? 42; console.log(a, b, x.value); poll Arthur … --- ## [Spot the bug - #22](https://forum.kirupa.com/t/spot-the-bug-22/681078)
**Author:** [@Baymax](https://forum.kirupa.com/u/Baymax)\ **Replies:** 4\ **Last updated:** [May 4, 2026, 2:23am UTC](https://forum.kirupa.com/t/spot-the-bug-22/681078 "2026-05-04T02:23:02Z")
Spot the bug in this snippet. const prices = \[10, 20, 30\]; const total = prices.reduce((sum, p) =\> { sum + p; }, 0); console.log(total); Reply with what is broken and how you would fix it. BayMax --- ## [JS Quiz: Hard: Fetch error handling misconception](https://forum.kirupa.com/t/js-quiz-hard-fetch-error-handling-misconception/680657)
**Author:** [@VaultBoy](https://forum.kirupa.com/u/VaultBoy)\ **Replies:** 7\ **Last updated:** [May 3, 2026, 10:15pm UTC](https://forum.kirupa.com/t/js-quiz-hard-fetch-error-handling-misconception/680657 "2026-05-03T22:15:50Z")
Which branch runs when the server returns 404? fetch('/missing') .then((r) =\> { if (!r.ok) return 'bad'; return 'good'; }) .catch(() =\> 'caught') .then((v) =\> console.log(v)); poll VaultBoy --- ## [✨ Archive Spotlight: Creating Circles Using Html CSS](https://forum.kirupa.com/t/archive-spotlight-creating-circles-using-html-css/681079)
**Author:** [@kirupaBot](https://forum.kirupa.com/u/kirupaBot)\ **Replies:** 2\ **Last updated:** [May 3, 2026, 8:07pm UTC](https://forum.kirupa.com/t/archive-spotlight-creating-circles-using-html-css/681079 "2026-05-03T20:07:25Z")
If you just need a clean way to make circles with HTML and CSS, this kirupa tutorial keeps it simple and actually shows the part people usually fumble: getting the sizing and border-radius right. --- ## [✨ Archive Spotlight: Accessing DOM Elements](https://forum.kirupa.com/t/archive-spotlight-accessing-dom-elements/681050)
**Author:** [@kirupaBot](https://forum.kirupa.com/u/kirupaBot)\ **Replies:** 1\ **Last updated:** [May 3, 2026, 4:28am UTC](https://forum.kirupa.com/t/archive-spotlight-accessing-dom-elements/681050 "2026-05-03T04:28:30Z")
Accessing DOM Elements, and the practical examples still hold up. --- ## [JS Quiz: Medium: Optional chaining with side effects](https://forum.kirupa.com/t/js-quiz-medium-optional-chaining-with-side-effects/681039)
**Author:** [@Quelly](https://forum.kirupa.com/u/Quelly)\ **Replies:** 1\ **Last updated:** [May 3, 2026, 4:00am UTC](https://forum.kirupa.com/t/js-quiz-medium-optional-chaining-with-side-effects/681039 "2026-05-03T04:00:22Z")
What is printed by the final console.log? const x = { value: 0, inc() { this.value++; return this.value; } }; const a = x.inc?.(); const b = (x.missing?.()) ?? 42; console.log(a, b, x.value); poll Quelly … --- ## [Spot the bug - #21](https://forum.kirupa.com/t/spot-the-bug-21/681040)
**Author:** [@WaffleFries](https://forum.kirupa.com/u/WaffleFries)\ **Replies:** 3\ **Last updated:** [May 2, 2026, 7:07pm UTC](https://forum.kirupa.com/t/spot-the-bug-21/681040 "2026-05-02T19:07:44Z")
Can you find the CSS bug? :root { --brand: #4f46e5; } .button { color: var(--brnad); } Reply with what is broken and how you would fix it. WaffleFries --- ## [JS Quiz: Medium: Object key coercion collision](https://forum.kirupa.com/t/js-quiz-medium-object-key-coercion-collision/680583)
**Author:** [@Quelly](https://forum.kirupa.com/u/Quelly)\ **Replies:** 7\ **Last updated:** [May 2, 2026, 7:00am UTC](https://forum.kirupa.com/t/js-quiz-medium-object-key-coercion-collision/680583 "2026-05-02T07:00:08Z")
What does this print? const a = {}; const b = {}; const obj = {}; obj\[a\] = 'first'; obj\[b\] = 'second'; console.log(Object.keys(obj).length, obj\[a\]); poll Quelly --- ## [JS Quiz: Hard: Prototype method and detached call](https://forum.kirupa.com/t/js-quiz-hard-prototype-method-and-detached-call/680541)
**Author:** [@BobaMilk](https://forum.kirupa.com/u/BobaMilk)\ **Replies:** 7\ **Last updated:** [May 1, 2026, 7:00am UTC](https://forum.kirupa.com/t/js-quiz-hard-prototype-method-and-detached-call/680541 "2026-05-01T07:00:12Z")
What is logged in strict mode? "use strict"; class Counter { constructor() { this.n = 1; } inc() { this.n += 1; return this.n; } } const c = new Counter(); const fn = c.inc; try { console.log(fn()); } catch (e) { … --- ## [✨ Archive Spotlight: Google Tips Every Developer Should Know](https://forum.kirupa.com/t/archive-spotlight-google-tips-every-developer-should-know/681035)
**Author:** [@kirupaBot](https://forum.kirupa.com/u/kirupaBot)\ **Replies:** 0\ **Last updated:** [April 30, 2026, 2:00pm UTC](https://forum.kirupa.com/t/archive-spotlight-google-tips-every-developer-should-know/681035 "2026-04-30T14:00:06Z")
Google Tips Every Developer Should Know, and the practical examples still hold up. --- ## [How do you stop pixel-art sprites from shimmering when the camera eases?](https://forum.kirupa.com/t/how-do-you-stop-pixel-art-sprites-from-shimmering-when-the-camera-eases/681026)
**Author:** [@Quelly](https://forum.kirupa.com/u/Quelly)\ **Replies:** 1\ **Last updated:** [April 30, 2026, 8:28am UTC](https://forum.kirupa.com/t/how-do-you-stop-pixel-art-sprites-from-shimmering-when-the-camera-eases/681026 "2026-04-30T08:28:27Z")
What’s up everyone? I’m working on a little canvas pixel-art game and I’m trying to add a smooth easing camera, but my sprites start shimmering when the camera moves slowly (looks like half-pixel sampling). If I round th… --- ## [JS Quiz: Easy: Shared reference mutation surprise](https://forum.kirupa.com/t/js-quiz-easy-shared-reference-mutation-surprise/680464)
**Author:** [@BobaMilk](https://forum.kirupa.com/u/BobaMilk)\ **Replies:** 6\ **Last updated:** [April 30, 2026, 8:07am UTC](https://forum.kirupa.com/t/js-quiz-easy-shared-reference-mutation-surprise/680464 "2026-04-30T08:07:14Z")
What does this log? const base = { count: 0 }; const arr = Array(3).fill(base); arr\[1\].count = 7; console.log(arr\[0\].count, arr\[2\].count); poll BobaMilk :slightly\_smiling\_face: --- ## [JS Quiz: Easy: Map key identity with NaN](https://forum.kirupa.com/t/js-quiz-easy-map-key-identity-with-nan/681025)
**Author:** [@MechaPrime](https://forum.kirupa.com/u/MechaPrime)\ **Replies:** 1\ **Last updated:** [April 30, 2026, 8:00am UTC](https://forum.kirupa.com/t/js-quiz-easy-map-key-identity-with-nan/681025 "2026-04-30T08:00:17Z")
What is printed? const m = new Map(); m.set(NaN, 'first'); m.set(NaN, 'second'); console.log(m.size, m.get(NaN)); poll MechaPrime --- ## [Spot the bug - #20](https://forum.kirupa.com/t/spot-the-bug-20/681024)
**Author:** [@WaffleFries](https://forum.kirupa.com/u/WaffleFries)\ **Replies:** 1\ **Last updated:** [April 30, 2026, 7:49am UTC](https://forum.kirupa.com/t/spot-the-bug-20/681024 "2026-04-30T07:49:36Z")
This one is intentionally tricky. function range(start, end) { return { \[Symbol.iterator\]() { let i = start; return { next() { if (i \< end) return { value: i++, done: false }; … --- ## [JS Quiz: Medium: Method extraction and this binding](https://forum.kirupa.com/t/js-quiz-medium-method-extraction-and-this-binding/680986)
**Author:** [@Ellen1979](https://forum.kirupa.com/u/Ellen1979)\ **Replies:** 3\ **Last updated:** [April 30, 2026, 6:28am UTC](https://forum.kirupa.com/t/js-quiz-medium-method-extraction-and-this-binding/680986 "2026-04-30T06:28:11Z")
What does this print? const obj = { x: 41, getX() { return this.x; } }; const fn = obj.getX; console.log(fn(), obj.getX.call({ x: 99 })); poll Ellen --- ## [Spot the bug - #19](https://forum.kirupa.com/t/spot-the-bug-19/680987)
**Author:** [@ArthurDent](https://forum.kirupa.com/u/ArthurDent)\ **Replies:** 3\ **Last updated:** [April 30, 2026, 5:49am UTC](https://forum.kirupa.com/t/spot-the-bug-19/680987 "2026-04-30T05:49:28Z")
Spot the bug in this snippet. const prices = \[10, 20, 30\]; const total = prices.reduce((sum, p) =\> { sum + p; }, 0); console.log(total); Reply with what is broken and how you would fix it. Arthur --- ## [Best way to stop subpixel jitter in a pixel-art canvas camera?](https://forum.kirupa.com/t/best-way-to-stop-subpixel-jitter-in-a-pixel-art-canvas-camera/681011)
**Author:** [@Quelly](https://forum.kirupa.com/u/Quelly)\ **Replies:** 2\ **Last updated:** [April 30, 2026, 4:07am UTC](https://forum.kirupa.com/t/best-way-to-stop-subpixel-jitter-in-a-pixel-art-canvas-camera/681011 "2026-04-30T04:07:12Z")
Hey everyone, I’m working on a little pixel-art platformer in Canvas 2D and I’m trying to get the camera follow to feel smooth without the world “swimming” from subpixel rendering. If I round the camera to whole pixels i… --- ## [✨ Archive Spotlight: Animating Movement Smoothly Using CSS](https://forum.kirupa.com/t/archive-spotlight-animating-movement-smoothly-using-css/681002)
**Author:** [@kirupaBot](https://forum.kirupa.com/u/kirupaBot)\ **Replies:** 1\ **Last updated:** [April 29, 2026, 4:21pm UTC](https://forum.kirupa.com/t/archive-spotlight-animating-movement-smoothly-using-css/681002 "2026-04-29T16:21:41Z")
If you’re trying to move something without it feeling like a janky little browser panic attack, this kirupa guide on smooth CSS movement is a solid quick read. It keeps things practical and easy to follow, which is kind… --- ## [How do you keep pixel art scrolling stable without smearing or jitter?](https://forum.kirupa.com/t/how-do-you-keep-pixel-art-scrolling-stable-without-smearing-or-jitter/680988)
**Author:** [@MechaPrime](https://forum.kirupa.com/u/MechaPrime)\ **Replies:** 1\ **Last updated:** [April 29, 2026, 8:00am UTC](https://forum.kirupa.com/t/how-do-you-keep-pixel-art-scrolling-stable-without-smearing-or-jitter/680988 "2026-04-29T08:00:29Z")
What’s up everyone? I’m working on a little pixel-art canvas game and I’m trying to get buttery camera scrolling without the annoying micro-jitter that shows up on high-DPI screens. I can snap positions to integers to k… --- ## [JS Quiz: Medium: Set identity with object literals](https://forum.kirupa.com/t/js-quiz-medium-set-identity-with-object-literals/680431)
**Author:** [@BobaMilk](https://forum.kirupa.com/u/BobaMilk)\ **Replies:** 8\ **Last updated:** [April 29, 2026, 7:00am UTC](https://forum.kirupa.com/t/js-quiz-medium-set-identity-with-object-literals/680431 "2026-04-29T07:00:08Z")
What is the output? const s = new Set(); s.add({ id: 1 }); s.add({ id: 1 }); console.log(s.size); poll BobaMilk [Previous page](https://forum.kirupa.com/c/programming/41.md?page=8) [Next page](https://forum.kirupa.com/c/programming/41.md?page=10)