[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"verticals":3,"playground-react-weekly-viewtransition-component":44,"search-suggestions":58},[4,20,32],{"id":5,"slug":6,"name":7,"tagline":8,"description":9,"accentFrom":10,"accentTo":11,"icon":12,"defaultLocale":13,"locales":14,"features":16,"position":19},"019fe637-3d33-714b-b57f-23e163ffca0c","dev","Web Development","Read it. Run it. Prove it.","A post a day on modern web development — most with an editable playground and a quiz that explains every answer. Free, no account needed.","violet-500","cyan-400","◇","en",[13,15],"fa",{"courses":17,"paths":17,"articles":17,"exams":18,"flashcards":18,"packages":17,"community":17,"certificates":17,"teams":17,"commerce":17},true,false,0,{"id":21,"slug":22,"name":23,"tagline":24,"description":25,"accentFrom":26,"accentTo":10,"icon":27,"defaultLocale":13,"locales":28,"features":30,"position":31},"019fe637-3dc2-754c-8657-0f175bfee7c6","lang","Languages","Learn a language the way you learn a codebase.","Grammar explained the way good documentation explains an API — one idea at a time, each with a quiz.","amber-400","⌘",[13,15,29],"es",{"courses":18,"paths":18,"articles":17,"exams":18,"flashcards":17,"packages":18,"community":17,"certificates":17,"teams":18,"commerce":18},2,{"id":33,"slug":34,"name":35,"tagline":36,"description":37,"accentFrom":38,"accentTo":39,"icon":40,"defaultLocale":13,"locales":41,"features":42,"position":43},"7b3c16f2-931d-410e-802e-e1fa4edab7de","soft","Soft Skills","The half of the job nobody wrote documentation for.","Weekly, on the parts of working life that decide more than your code does — first weeks, meetings, interviews, promotions, and the people around you. Written from what actually happens, and recorded as a podcast you can listen to on the walk.","emerald-400","teal-300","◉",[13],{"courses":18,"paths":18,"articles":17,"exams":18,"flashcards":18,"packages":18,"community":17,"certificates":18,"teams":18,"commerce":18},3,{"slug":45,"title":46,"summary":47,"html":48,"css":49,"js":50,"config":51,"doc":53},"react-weekly-viewtransition-component","React ViewTransition — interactive playground",null,"\u003Cdiv class=\"pg\">\n    \u003Ch1 class=\"pg-title\">🎮 ViewTransition, live\u003C\u002Fh1>\n    \u003Cp class=\"pg-sub\">\n      Click a photo to open it, add\u002Fremove one, or toggle a caption. With\n      \u003Cb>Real Transition\u003C\u002Fb> on, every change is wrapped in \u003Ccode>startTransition\u003C\u002Fcode> so any\n      \u003Ccode><ViewTransition>\u003C\u002Fcode> below can react to it. Flip it off and the exact same\n      state changes happen — \u003Ccode><ViewTransition>\u003C\u002Fcode> just goes inert, because there's\n      no Transition for it to key off.\n    \u003C\u002Fp>\n\n    \u003Cdiv class=\"banner info show\" id=\"boot\">Loading the real React 19.3.0 runtime from the CDN…\u003C\u002Fdiv>\n\n    \u003Cdiv id=\"app\" hidden>\u003C\u002Fdiv>\n  \u003C\u002Fdiv>","\u002F*\n * Shared playground design system — daily-post\n * ============================================\n * Link it from any post's playground\u002Findex.html (no per-post boilerplate):\n *\n *   \u003Clink rel=\"stylesheet\" href=\"..\u002F..\u002F..\u002Fplayground\u002Fassets\u002Fbase.css\" \u002F>\n *\n * The relative path resolves the same locally (posts\u002F\u003Cbase>\u002Fplayground\u002F) and on\n * the deployed host (public\u002Fposts\u002F\u003Cbase>\u002Fplayground\u002F), because build-site.js\n * mirrors this file to public\u002Fplayground\u002Fassets\u002Fbase.css. For a CodeSandbox\n * --embed, playground.js inlines this file so the single-file sandbox still styles.\n *\n * Then write ONLY the demo-specific CSS in your inline \u003Cstyle>. Everything below\n * — tokens, layout, panels, buttons, toggles, sliders, code blocks, status\u002Flog,\n * banners, presets — comes for free and looks consistent across every post.\n *\n * Theme-aware: dark by default, light via prefers-color-scheme AND a\n * [data-theme] override on \u003Chtml> (so a toggle can force either). Accessible:\n * real focus rings, adequate contrast, reduced-motion honored.\n *\u002F\n\n\u002F* ---------- design tokens ---------- *\u002F\n:root {\n  --bg: #0d1117;\n  --bg-grid: #ffffff0a;\n  --panel: #161b22;\n  --panel-2: #0b0e14;\n  --card: #0b0e14;\n  --ink: #e8ebf2;\n  --muted: #9aa4b2;\n  --faint: #6b7688;\n  --line: #232a35;\n  --line-soft: #ffffff12;\n  --accent: #7c9cff;\n  --accent-ink: #0b0e14;\n  --good: #3fb950;\n  --warn: #f0883e;\n  --bad: #f85149;\n  --info: #58a6ff;\n  --radius: 14px;\n  --radius-sm: 9px;\n  --shadow: 0 8px 30px #0006;\n  --shadow-sm: 0 4px 14px #0005;\n  --mono: ui-monospace, SFMono-Regular, \"SF Mono\", Menlo, Consolas, \"Liberation Mono\", monospace;\n  --sans: ui-sans-serif, system-ui, -apple-system, \"Segoe UI\", Roboto, \"Helvetica Neue\", sans-serif;\n  color-scheme: dark;\n}\n\n\u002F* Light theme — system preference, overridable by [data-theme] on \u003Chtml>. *\u002F\n@media (prefers-color-scheme: light) {\n  :root:not([data-theme=\"dark\"]) {\n    --bg: #f4f6fb;\n    --bg-grid: #00000008;\n    --panel: #ffffff;\n    --panel-2: #f0f3f9;\n    --card: #f7f9fc;\n    --ink: #131722;\n    --muted: #5b6472;\n    --faint: #8a93a3;\n    --line: #e2e7f0;\n    --line-soft: #00000010;\n    --accent: #2f6df0;\n    --accent-ink: #ffffff;\n    --good: #1a7f37;\n    --warn: #bc4c00;\n    --bad: #cf222e;\n    --info: #0969da;\n    --shadow: 0 8px 30px #0000001f;\n    --shadow-sm: 0 4px 14px #00000014;\n    color-scheme: light;\n  }\n}\n:root[data-theme=\"light\"] {\n  --bg: #f4f6fb;\n  --bg-grid: #00000008;\n  --panel: #ffffff;\n  --panel-2: #f0f3f9;\n  --card: #f7f9fc;\n  --ink: #131722;\n  --muted: #5b6472;\n  --faint: #8a93a3;\n  --line: #e2e7f0;\n  --line-soft: #00000010;\n  --accent: #2f6df0;\n  --accent-ink: #ffffff;\n  --good: #1a7f37;\n  --warn: #bc4c00;\n  --bad: #cf222e;\n  --info: #0969da;\n  --shadow: 0 8px 30px #0000001f;\n  --shadow-sm: 0 4px 14px #00000014;\n  color-scheme: light;\n}\n\n\u002F* ---------- reset & base ---------- *\u002F\n*, *::before, *::after { box-sizing: border-box; }\n\nbody {\n  margin: 0;\n  min-height: 100vh;\n  font-family: var(--sans);\n  color: var(--ink);\n  background:\n    radial-gradient(circle at 1px 1px, var(--bg-grid) 1px, transparent 0) 0 0 \u002F 24px 24px,\n    var(--bg);\n  display: flex;\n  justify-content: center;\n  align-items: flex-start;\n  padding: clamp(14px, 3vw, 26px);\n  line-height: 1.55;\n  -webkit-font-smoothing: antialiased;\n  text-rendering: optimizeLegibility;\n}\n\n\u002F* The single content column. *\u002F\n.pg {\n  width: 100%;\n  max-width: 860px;\n}\n\n\u002F* ---------- header ---------- *\u002F\n.pg-title {\n  font-size: clamp(1.15rem, 1rem + 1vw, 1.4rem);\n  font-weight: 800;\n  letter-spacing: -0.02em;\n  margin: 0 0 4px;\n  display: flex;\n  align-items: center;\n  gap: 9px;\n}\n.pg-sub {\n  color: var(--muted);\n  font-size: 0.92rem;\n  line-height: 1.5;\n  margin: 0 0 16px;\n  max-width: 66ch;\n}\n.pg-sub strong, .pg-sub b { color: var(--ink); font-weight: 700; }\n.pg-sub code { font-family: var(--mono); background: var(--line-soft); color: var(--accent);\n  padding: 1px 6px; border-radius: 6px; font-size: 0.85em; }\n\n\u002F* ---------- panels ---------- *\u002F\n.panel {\n  background: var(--panel);\n  border: 1px solid var(--line);\n  border-radius: var(--radius);\n  padding: 16px 18px;\n  margin-bottom: 14px;\n  box-shadow: var(--shadow-sm);\n}\n.panel-label {\n  font-size: 0.7rem;\n  text-transform: uppercase;\n  letter-spacing: 0.08em;\n  color: var(--muted);\n  font-weight: 800;\n  margin: 0 0 13px;\n  display: flex;\n  align-items: center;\n  gap: 8px;\n}\n.panel-label .n {\n  display: inline-grid; place-items: center;\n  width: 18px; height: 18px; border-radius: 50%;\n  background: var(--accent); color: var(--accent-ink);\n  font-size: 0.66rem; font-weight: 800;\n}\n\n\u002F* ---------- layout helpers ---------- *\u002F\n.row { display: flex; flex-wrap: wrap; gap: 12px; align-items: center; }\n.row.between { justify-content: space-between; }\n.col { display: flex; flex-direction: column; gap: 10px; }\n.grow { flex: 1 1 0; min-width: 0; }\n.wrap-controls { display: flex; flex-wrap: wrap; gap: 16px 24px; align-items: flex-end; }\n.field { display: flex; flex-direction: column; gap: 7px; min-width: 0; }\n.field > .label, .ctl-label {\n  font-size: 0.7rem; text-transform: uppercase; letter-spacing: 0.04em;\n  color: var(--muted); font-weight: 800;\n}\n\n\u002F* ---------- buttons ---------- *\u002F\n.btn {\n  font: inherit; font-weight: 650; font-size: 0.88rem;\n  cursor: pointer; user-select: none;\n  border: 1px solid var(--line);\n  background: var(--card); color: var(--ink);\n  padding: 9px 15px; border-radius: var(--radius-sm);\n  display: inline-flex; align-items: center; gap: 8px;\n  transition: background .15s ease, border-color .15s ease, transform .05s ease, color .15s ease;\n}\n.btn:hover { background: var(--line-soft); border-color: var(--muted); }\n.btn:active { transform: translateY(1px); }\n.btn:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }\n.btn[disabled] { opacity: 0.45; cursor: not-allowed; }\n.btn.primary { background: var(--accent); border-color: var(--accent); color: var(--accent-ink); }\n.btn.primary:hover { filter: brightness(1.08); background: var(--accent); }\n.btn.good { background: var(--good); border-color: var(--good); color: #04140a; }\n.btn.bad  { background: var(--bad);  border-color: var(--bad);  color: #fff; }\n.btn.ghost { background: transparent; }\n.btn.sm { padding: 6px 11px; font-size: 0.82rem; }\n\n.btn-row { display: flex; flex-wrap: wrap; gap: 9px; }\n\n\u002F* Segmented control — a row of buttons where one is active (aria-pressed). *\u002F\n.seg { display: inline-flex; background: var(--card); border: 1px solid var(--line);\n  border-radius: var(--radius-sm); padding: 3px; gap: 3px; }\n.seg button {\n  font: inherit; font-weight: 650; font-size: 0.84rem; cursor: pointer;\n  border: none; background: transparent; color: var(--muted);\n  padding: 7px 13px; border-radius: 7px;\n  transition: background .15s ease, color .15s ease;\n}\n.seg button:hover { color: var(--ink); }\n.seg button[aria-pressed=\"true\"] { background: var(--accent); color: var(--accent-ink); }\n.seg button:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }\n\n\u002F* Preset chips — worked-example shortcuts. *\u002F\n.presets { display: flex; flex-wrap: wrap; gap: 8px; }\n.presets .btn { background: var(--panel-2); }\n\n\u002F* ---------- toggle switch ---------- *\u002F\n.toggle { display: inline-flex; align-items: center; gap: 10px; cursor: pointer;\n  font-size: 0.88rem; font-weight: 600; user-select: none; }\n.toggle input { position: absolute; opacity: 0; width: 0; height: 0; }\n.switch { position: relative; width: 44px; height: 25px; border-radius: 999px; flex: none;\n  background: var(--line); border: 1px solid var(--line); transition: background .18s ease; }\n.switch::after { content: \"\"; position: absolute; top: 2px; left: 2px; width: 19px; height: 19px;\n  border-radius: 50%; background: #cfd6e4; transition: transform .18s ease; box-shadow: 0 1px 3px #0006; }\n.toggle input:checked + .switch { background: var(--good); border-color: var(--good); }\n.toggle input:checked + .switch::after { transform: translateX(19px); background: #fff; }\n.toggle input:focus-visible + .switch { outline: 2px solid var(--accent); outline-offset: 2px; }\n\n\u002F* ---------- range slider ---------- *\u002F\ninput[type=\"range\"] {\n  -webkit-appearance: none; appearance: none; width: 100%; height: 6px;\n  background: var(--line); border-radius: 999px; outline: none; cursor: pointer; margin: 8px 0;\n}\ninput[type=\"range\"]::-webkit-slider-thumb {\n  -webkit-appearance: none; appearance: none; width: 19px; height: 19px; border-radius: 50%;\n  background: var(--accent); border: 2px solid var(--panel); box-shadow: var(--shadow-sm); cursor: pointer;\n}\ninput[type=\"range\"]::-moz-range-thumb {\n  width: 19px; height: 19px; border-radius: 50%; background: var(--accent);\n  border: 2px solid var(--panel); box-shadow: var(--shadow-sm); cursor: pointer;\n}\ninput[type=\"range\"]:focus-visible { outline: 2px solid var(--accent); outline-offset: 3px; }\n\n\u002F* ---------- text inputs \u002F selects ---------- *\u002F\ninput[type=\"text\"], input[type=\"number\"], input[type=\"search\"], select, textarea {\n  font: inherit; color: var(--ink); background: var(--card);\n  border: 1px solid var(--line); border-radius: var(--radius-sm); padding: 8px 11px; width: 100%;\n}\ntextarea { font-family: var(--mono); font-size: 0.85rem; line-height: 1.6; resize: vertical; }\ninput:focus-visible, select:focus-visible, textarea:focus-visible {\n  outline: 2px solid var(--accent); outline-offset: 1px; border-color: var(--accent);\n}\n\n\u002F* ---------- status \u002F output \u002F log ---------- *\u002F\n.status {\n  display: flex; align-items: center; gap: 9px; flex-wrap: wrap;\n  font-size: 0.9rem; font-weight: 600;\n  padding: 11px 14px; border-radius: var(--radius-sm);\n  background: var(--panel-2); border: 1px solid var(--line); color: var(--ink);\n}\n.status.good { border-color: color-mix(in srgb, var(--good) 55%, var(--line)); }\n.status.warn { border-color: color-mix(in srgb, var(--warn) 55%, var(--line)); }\n.status.bad  { border-color: color-mix(in srgb, var(--bad) 55%, var(--line)); }\n.dot { width: 9px; height: 9px; border-radius: 50%; background: var(--muted); flex: none; }\n.dot.good { background: var(--good); } .dot.warn { background: var(--warn); }\n.dot.bad { background: var(--bad); } .dot.info { background: var(--info); }\n\n.output { background: var(--panel-2); border: 1px solid var(--line); border-radius: var(--radius-sm);\n  padding: 13px 15px; }\n.log { font-family: var(--mono); font-size: 0.8rem; line-height: 1.7; background: var(--card);\n  border: 1px solid var(--line); border-radius: var(--radius-sm); padding: 11px 14px;\n  max-height: 220px; overflow-y: auto; white-space: pre-wrap; }\n\n\u002F* ---------- code block + syntax tokens ---------- *\u002F\n.code {\n  font-family: var(--mono); font-size: 0.82rem; line-height: 1.7;\n  background: var(--panel-2); border: 1px solid var(--line); border-radius: var(--radius-sm);\n  padding: 13px 15px; overflow-x: auto; white-space: pre; tab-size: 2;\n}\n.code .tok-sel  { color: var(--accent); }\n.code .tok-prop { color: #86e29b; }\n.code .tok-kw   { color: #ff9bcb; }\n.code .tok-str  { color: #f0c674; }\n.code .tok-num  { color: #f0883e; }\n.code .tok-cmt  { color: var(--faint); font-style: italic; }\n.code .hl { background: color-mix(in srgb, var(--good) 22%, transparent); border-radius: 4px; padding: 0 3px; }\n\n\u002F* ---------- hint \u002F caption ---------- *\u002F\n.hint { font-size: 0.83rem; color: var(--muted); line-height: 1.55; margin: 10px 0 0; }\n.hint code { font-family: var(--mono); color: var(--ink); background: var(--line-soft);\n  padding: 1px 5px; border-radius: 5px; font-size: 0.86em; }\n.hint strong { color: var(--ink); }\n\n\u002F* ---------- banner (feature-support \u002F notices) ---------- *\u002F\n.banner {\n  display: none; margin-bottom: 14px; padding: 11px 14px; border-radius: 11px;\n  font-size: 0.85rem; line-height: 1.5;\n  color: var(--ink); background: color-mix(in srgb, var(--warn) 12%, var(--panel));\n  border: 1px solid color-mix(in srgb, var(--warn) 45%, var(--line));\n}\n.banner.show { display: block; }\n.banner.info { background: color-mix(in srgb, var(--info) 12%, var(--panel));\n  border-color: color-mix(in srgb, var(--info) 45%, var(--line)); }\n.banner code { font-family: var(--mono); background: var(--line-soft); padding: 1px 5px; border-radius: 5px; }\n\n\u002F* ---------- misc atoms ---------- *\u002F\n.pill { display: inline-flex; align-items: center; gap: 6px; font-size: 0.75rem; font-weight: 700;\n  padding: 3px 9px; border-radius: 999px; background: var(--line-soft); color: var(--muted); }\n.pill.good { color: var(--good); background: color-mix(in srgb, var(--good) 16%, transparent); }\n.pill.bad  { color: var(--bad);  background: color-mix(in srgb, var(--bad) 16%, transparent); }\n.mono { font-family: var(--mono); }\n.muted { color: var(--muted); }\n.big-num { font-family: var(--mono); font-size: 1.6rem; font-weight: 800; letter-spacing: -0.02em; }\n\n\u002F* Optional theme toggle button (top-right). Wire it in JS if you want it. *\u002F\n.theme-btn { position: fixed; top: 12px; right: 12px; z-index: 20; }\n\n\u002F* ---------- responsive ---------- *\u002F\n@media (max-width: 560px) {\n  .panel { padding: 14px; }\n  .wrap-controls { gap: 14px; }\n  .btn { padding: 9px 13px; }\n}\n\n\u002F* ---------- reduced motion ---------- *\u002F\n@media (prefers-reduced-motion: reduce) {\n  *, *::before, *::after { transition-duration: 0.01ms !important; animation-duration: 0.01ms !important; }\n}\n\n\n\u002F* Demo-specific only — base.css owns tokens, panels, buttons, status, log. *\u002F\n  .grid {\n    display: grid; grid-template-columns: repeat(auto-fill, minmax(96px, 1fr));\n    gap: 10px; margin-top: 12px;\n  }\n  .thumb {\n    aspect-ratio: 1; border-radius: var(--radius-sm); border: 1px solid var(--line);\n    display: flex; align-items: center; justify-content: center; font-size: 2rem;\n    cursor: pointer; color: #fff; user-select: none; background: none;\n  }\n  .thumb:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }\n  .card {\n    border: 1px solid var(--line); border-radius: var(--radius-sm); padding: 10px 12px;\n    background: var(--panel-2); margin-top: 12px;\n  }\n  .card .caption { margin: 0; }\n  .card .detail { margin: 8px 0 0; color: var(--muted); font-size: 0.85rem; }\n  .detail-panel {\n    margin-top: 12px; border: 1px solid var(--line); border-radius: var(--radius-sm);\n    padding: 16px; background: var(--panel-2); display: flex; gap: 14px; align-items: center;\n  }\n  .detail-hero {\n    width: 96px; height: 96px; border-radius: var(--radius-sm); flex: none;\n    display: flex; align-items: center; justify-content: center; font-size: 3rem; color: #fff;\n  }\n  .unsupported {\n    margin-top: 10px; padding: 8px 12px; border-radius: var(--radius-sm); font-size: 0.82rem;\n    background: color-mix(in srgb, var(--warn) 16%, var(--panel-2));\n    border: 1px solid color-mix(in srgb, var(--warn) 45%, var(--line));\n  }","const $ = (id) => document.getElementById(id);\n\nlet React, createRoot;\ntry {\n  \u002F\u002F Pinned to the exact version the article verifies.\n  [React, { createRoot }] = await Promise.all([\n    import(\"https:\u002F\u002Fesm.sh\u002Freact@19.3.0\"),\n    import(\"https:\u002F\u002Fesm.sh\u002Freact-dom@19.3.0\u002Fclient?deps=react@19.3.0\"),\n  ]);\n} catch (err) {\n  $(\"boot\").className = \"banner show\";\n  $(\"boot\").innerHTML =\n    \"\u003Cb>React couldn't load from the CDN\u003C\u002Fb> — you're offline, or a network policy blocked esm.sh. \" +\n    \"This demo deliberately runs the \u003Cem>real\u003C\u002Fem> React reconciler and the real \" +\n    \"\u003Ccode><ViewTransition>\u003C\u002Fcode> component rather than imitating them, so there's nothing \" +\n    \"honest to show without it. The article's code samples stand on their own; try again with a \" +\n    \"connection.\";\n  throw err;\n}\n\nconst { createElement: h, useState, useEffect, startTransition, ViewTransition } = React;\n\nif (!ViewTransition) {\n  $(\"boot\").className = \"banner show\";\n  $(\"boot\").innerHTML =\n    \"\u003Cb>This build of React doesn't export \u003Ccode>ViewTransition\u003C\u002Fcode>.\u003C\u002Fb> The article verifies \" +\n    \"against React 19.3.0, where it's stable — if the CDN served something older, the exact-version \" +\n    \"pin above didn't resolve as expected.\";\n  throw new Error(\"ViewTransition not found on React export\");\n}\n\n$(\"boot\").hidden = true;\n$(\"app\").hidden = false;\n$(\"app\").innerHTML = `\n  \u003Cdiv class=\"panel\">\n    \u003Cdiv class=\"panel-label\">\u003Cspan class=\"n\">1\u003C\u002Fspan> Transition mode\u003C\u002Fdiv>\n    \u003Clabel class=\"toggle\">\n      \u003Cinput type=\"checkbox\" id=\"transitionToggle\" checked \u002F>\n      \u003Cspan class=\"switch\">\u003C\u002Fspan>\n      \u003Cspan>Real Transition: wrap every change in \u003Ccode>startTransition\u003C\u002Fcode>\u003C\u002Fspan>\n    \u003C\u002Flabel>\n    \u003Cp class=\"hint\" id=\"modeHint\" style=\"margin-top:8px\">\u003C\u002Fp>\n    \u003Cdiv id=\"unsupportedBanner\" class=\"unsupported\" hidden>\n      ⚠️ This browser doesn't expose \u003Ccode>document.startViewTransition\u003C\u002Fcode>, so React skips the\n      animation and applies the DOM change instantly — the update itself still works, exactly as the\n      article's \"graceful fallback\" gotcha describes.\n    \u003C\u002Fdiv>\n  \u003C\u002Fdiv>\n  \u003Cdiv class=\"panel\" style=\"margin-top:16px\">\n    \u003Cdiv class=\"panel-label\">\n      \u003Cspan class=\"n\">2\u003C\u002Fspan> Photo grid\n      \u003Cspan class=\"pill\" id=\"lastEvent\" style=\"margin-left:8px\">—\u003C\u002Fspan>\n    \u003C\u002Fdiv>\n    \u003Cdiv class=\"btn-row\">\n      \u003Cbutton class=\"btn ghost sm\" id=\"addBtn\">+ Add photo (enter)\u003C\u002Fbutton>\n      \u003Cbutton class=\"btn ghost sm\" id=\"removeBtn\">− Remove last (exit)\u003C\u002Fbutton>\n      \u003Cbutton class=\"btn ghost sm\" id=\"expandBtn\">Toggle caption on #1 (update)\u003C\u002Fbutton>\n    \u003C\u002Fdiv>\n    \u003Cdiv id=\"reactRoot\">\u003C\u002Fdiv>\n  \u003C\u002Fdiv>\n  \u003Cdiv class=\"panel\" style=\"margin-top:16px\">\n    \u003Cdiv class=\"panel-label\">\u003Cspan class=\"n\">3\u003C\u002Fspan> What just happened\u003C\u002Fdiv>\n    \u003Cp class=\"hint\" style=\"margin-top:0\">\n      Each line names the shape (\u003Ccode>enter\u003C\u002Fcode>\u002F\u003Ccode>exit\u003C\u002Fcode>\u002F\u003Ccode>update\u003C\u002Fcode>\u002F\u003Ccode>share\u003C\u002Fcode>)\n      the change should activate, and whether it ran inside a real Transition.\n    \u003C\u002Fp>\n    \u003Cdiv class=\"log\" id=\"log\" aria-live=\"polite\">\u003C\u002Fdiv>\n  \u003C\u002Fdiv>\n`;\nif (!document.startViewTransition) $(\"unsupportedBanner\").hidden = false;\n\nconst COLORS = [\"#5b8def\", \"#e5484d\", \"#f5a623\", \"#2fb380\", \"#8b5cf6\", \"#ec4899\"];\nconst EMOJI = [\"🏔️\", \"🌊\", \"🌵\", \"🌲\", \"🌸\", \"🦊\", \"🐙\", \"🍁\"];\nlet nextId = 6;\nconst INITIAL = Array.from({ length: 5 }, (_, i) => ({\n  id: i + 1,\n  color: COLORS[i % COLORS.length],\n  emoji: EMOJI[i % EMOJI.length],\n}));\n\nconst logEl = $(\"log\");\nfunction logLine(text, cls = \"\") {\n  const el = document.createElement(\"div\");\n  el.className = cls;\n  el.textContent = text;\n  logEl.prepend(el);\n  while (logEl.childElementCount > 40) logEl.lastElementChild.remove();\n}\n\nfunction Thumb({ photo, openId, onOpen }) {\n  \u002F\u002F While this photo is open in the detail panel, the grid copy is removed\n  \u002F\u002F from the tree entirely — that removal, paired with the matching `name`\n  \u002F\u002F mounting in the detail panel in the same Transition, is what makes this\n  \u002F\u002F a `share` activation instead of two unrelated enter\u002Fexit animations.\n  if (openId === photo.id) return null;\n  return h(\n    ViewTransition,\n    { name: `photo-${photo.id}`, update: \"auto\" },\n    h(\n      \"button\",\n      {\n        type: \"button\",\n        className: \"thumb\",\n        style: { background: photo.color },\n        \"aria-label\": `Open photo ${photo.id}`,\n        onClick: () => onOpen(photo.id),\n      },\n      photo.emoji\n    )\n  );\n}\n\nfunction DetailPanel({ photo, onClose }) {\n  if (!photo) return null;\n  return h(\n    ViewTransition,\n    { name: `photo-${photo.id}` },\n    h(\n      \"div\",\n      { className: \"detail-panel\" },\n      h(\"div\", { className: \"detail-hero\", style: { background: photo.color } }, photo.emoji),\n      h(\n        \"div\",\n        null,\n        h(\"p\", { style: { margin: 0, fontWeight: 700 } }, `Photo #${photo.id}, full size`),\n        h(\n          \"p\",\n          { className: \"hint\", style: { margin: \"4px 0 0\" } },\n          \"This panel and the thumbnail above share one name prop — React pairs the removal and the insertion into one animation.\"\n        ),\n        h(\"button\", { className: \"btn sm\", style: { marginTop: 8 }, onClick: onClose }, \"Close\")\n      )\n    )\n  );\n}\n\nfunction App() {\n  const [photos, setPhotos] = useState(INITIAL);\n  const [openId, setOpenId] = useState(null);\n  const [expanded, setExpanded] = useState(false);\n  const [realTransition, setRealTransition] = useState(true);\n\n  const runChange = (label, shape, fn) => {\n    if (realTransition) {\n      startTransition(fn);\n      logLine(`✅ ${label} — ran inside startTransition, ${shape} can activate`, \"good\");\n    } else {\n      fn();\n      logLine(`⏭️ ${label} — plain setState, ${shape} stays inert (no Transition)`);\n    }\n    $(\"lastEvent\").textContent = shape;\n  };\n\n  const openPhoto = (id) => runChange(`open photo #${id}`, \"share\", () => setOpenId(id));\n  const closePhoto = () => runChange(\"close photo\", \"share\", () => setOpenId(null));\n  const addPhoto = () =>\n    runChange(\"add photo\", \"enter\", () => {\n      const id = nextId++;\n      setPhotos((p) => [...p, { id, color: COLORS[id % COLORS.length], emoji: EMOJI[id % EMOJI.length] }]);\n    });\n  const removePhoto = () =>\n    runChange(\"remove last photo\", \"exit\", () => setPhotos((p) => (p.length > 1 ? p.slice(0, -1) : p)));\n  const toggleExpand = () => runChange(\"toggle caption on #1\", \"update\", () => setExpanded((e) => !e));\n\n  \u002F\u002F Wire the plain-DOM controls (outside this React root) to this render's\n  \u002F\u002F handlers. Re-runs every render, which is fine — it just reassigns onclick.\n  useEffect(() => {\n    $(\"transitionToggle\").onchange = (e) => setRealTransition(e.target.checked);\n    $(\"modeHint\").textContent = realTransition\n      ? \"Every click below runs inside startTransition.\"\n      : \"Every click below runs a plain setState — watch enter\u002Fexit\u002Fupdate\u002Fshare go inert.\";\n    $(\"addBtn\").onclick = addPhoto;\n    $(\"removeBtn\").onclick = removePhoto;\n    $(\"expandBtn\").onclick = toggleExpand;\n  });\n\n  const first = photos[0];\n  const openPhotoObj = photos.find((p) => p.id === openId) || null;\n\n  return h(\n    React.Fragment,\n    null,\n    h(\n      \"div\",\n      { className: \"grid\" },\n      photos.map((p) => h(Thumb, { key: p.id, photo: p, openId, onOpen: openPhoto }))\n    ),\n    h(\n      ViewTransition,\n      { update: \"auto\" },\n      h(\n        \"div\",\n        { className: \"card\" },\n        h(\"p\", { className: \"caption\" }, `Photo #${first ? first.id : \"—\"} — click \"Toggle caption\" above`),\n        expanded &&\n          h(\n            \"p\",\n            { className: \"detail\" },\n            \"Expanding this caption resizes the card — that resize is what activates update, on this card and on any sibling it pushes down.\"\n          )\n      )\n    ),\n    h(DetailPanel, { photo: openPhotoObj, onClose: closePhoto })\n  );\n}\n\ncreateRoot($(\"reactRoot\")).render(h(App));",{"height":52,"autorun":17},520,{"slug":45,"title":54,"excerpt":55,"coverUrl":56,"vertical":57},"React 19.3 ViewTransition: Animate State Without Losing It","React 19.3's ViewTransition component animates state changes, not just page swaps — the mental model, enter\u002Fexit\u002Fupdate\u002Fshare, and a cheat sheet.","\u002Fmedia\u002Fcovers\u002Freact-weekly-viewtransition-component.png",{"slug":6},[59,63,67,71,75,79,83,87,90,94,97,101],{"slug":60,"name":61,"articles":62},"webdev","Webdev",121,{"slug":64,"name":65,"articles":66},"javascript","Javascript",100,{"slug":68,"name":69,"articles":70},"frontend","Frontend",78,{"slug":72,"name":73,"articles":74},"tutorial","Tutorial",46,{"slug":76,"name":77,"articles":78},"css","Css",39,{"slug":80,"name":81,"articles":82},"typescript","Typescript",18,{"slug":84,"name":85,"articles":86},"react","React",15,{"slug":88,"name":89,"articles":86},"performance","Performance",{"slug":91,"name":92,"articles":93},"browser","Browser",11,{"slug":95,"name":96,"articles":93},"node","Node",{"slug":98,"name":99,"articles":100},"html","Html",8,{"slug":102,"name":103,"articles":104},"accessibility","Accessibility",7]