[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"verticals":3,"playground-array-from-async-async-iterable":32},[4,20],{"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","Build. Learn. Ship.","Practical courses, engineering-grade articles and open-source tools for people who ship.","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.","Structured paths, listening drills and spaced repetition that actually sticks.","amber-400","⌘",[13,15,29],"es",{"courses":17,"paths":17,"articles":18,"exams":18,"flashcards":18,"packages":18,"community":17,"certificates":18,"teams":18,"commerce":17},2,{"slug":33,"title":34,"summary":35,"html":36,"css":37,"js":38,"config":39,"doc":41},"array-from-async-async-iterable","Array.fromAsync — interactive playground",null,"\u003Cdiv class=\"pg\">\n    \u003Ch1 class=\"pg-title\">🎮 Array.fromAsync in action\u003C\u002Fh1>\n    \u003Cp class=\"pg-sub\">\n      An async generator drips out items one at a time. Try three ways to collect them all into a\n      plain array — only one requires zero boilerplate.\n    \u003C\u002Fp>\n\n    \u003Cdiv class=\"panel\">\n      \u003Cdiv class=\"panel-label\">\u003Cspan class=\"n\">1\u003C\u002Fspan> Configure the source\u003C\u002Fdiv>\n      \u003Cdiv class=\"wrap-controls\">\n        \u003Cdiv class=\"field\">\n          \u003Clabel class=\"label\" for=\"count\">Items to generate \u003Cspan class=\"mono\" id=\"countOut\">8\u003C\u002Fspan>\u003C\u002Flabel>\n          \u003Cinput type=\"range\" id=\"count\" min=\"4\" max=\"16\" step=\"1\" value=\"8\" \u002F>\n        \u003C\u002Fdiv>\n        \u003Cdiv class=\"field\">\n          \u003Clabel class=\"label\" for=\"delay\">Delay per item \u003Cspan class=\"mono\" id=\"delayOut\">120 ms\u003C\u002Fspan>\u003C\u002Flabel>\n          \u003Cinput type=\"range\" id=\"delay\" min=\"40\" max=\"400\" step=\"20\" value=\"120\" \u002F>\n        \u003C\u002Fdiv>\n      \u003C\u002Fdiv>\n      \u003Cp class=\"hint\">\n        Each call to \u003Ccode>next()\u003C\u002Fcode> on the async generator takes this long, simulating a real\n        async source (network page, database cursor, stream).\n      \u003C\u002Fp>\n    \u003C\u002Fdiv>\n\n    \u003Cdiv class=\"panel\">\n      \u003Cdiv class=\"panel-label\">\u003Cspan class=\"n\">2\u003C\u002Fspan> Pick an approach\u003C\u002Fdiv>\n      \u003Cdiv class=\"approach-btns\">\n        \u003Cbutton class=\"approach-btn\" id=\"btnSpread\">\n          \u003Cspan class=\"tag bad\">throws\u003C\u002Fspan>\n          \u003Cspan>\u003Cstrong>[...asyncGen()]\u003C\u002Fstrong> — spread an async iterable\u003C\u002Fspan>\n        \u003C\u002Fbutton>\n        \u003Cbutton class=\"approach-btn\" id=\"btnLoop\">\n          \u003Cspan class=\"tag warn\">works\u003C\u002Fspan>\n          \u003Cspan>\u003Cstrong>for await ... push\u003C\u002Fstrong> — manual loop into an array\u003C\u002Fspan>\n        \u003C\u002Fbutton>\n        \u003Cbutton class=\"approach-btn\" id=\"btnFromAsync\">\n          \u003Cspan class=\"tag good\">best\u003C\u002Fspan>\n          \u003Cspan>\u003Cstrong>await Array.fromAsync(asyncGen())\u003C\u002Fstrong> — one call\u003C\u002Fspan>\n        \u003C\u002Fbutton>\n      \u003C\u002Fdiv>\n    \u003C\u002Fdiv>\n\n    \u003Cdiv class=\"panel\">\n      \u003Cdiv class=\"panel-label\">\u003Cspan class=\"n\">3\u003C\u002Fspan> Watch it collect\u003C\u002Fdiv>\n      \u003Cdiv class=\"cards\" id=\"cards\" aria-label=\"collected items\">\u003C\u002Fdiv>\n      \u003Cdiv id=\"status\" class=\"status\" style=\"margin-top:8px\">\n        \u003Cspan class=\"dot info\" id=\"dot\">\u003C\u002Fspan>\n        \u003Cspan id=\"statusText\">Pick an approach above.\u003C\u002Fspan>\n      \u003C\u002Fdiv>\n      \u003Cdiv style=\"margin-top:10px\">\n        \u003Cdiv class=\"result-row\">\n          \u003Cspan class=\"result-label\">result →\u003C\u002Fspan>\n          \u003Cspan class=\"result-val\" id=\"resultVal\">—\u003C\u002Fspan>\n        \u003C\u002Fdiv>\n        \u003Cdiv class=\"result-row\" style=\"margin-top:4px\">\n          \u003Cspan class=\"result-label\">time →\u003C\u002Fspan>\n          \u003Cspan class=\"result-val\" id=\"timeVal\">—\u003C\u002Fspan>\n        \u003C\u002Fdiv>\n      \u003C\u002Fdiv>\n    \u003C\u002Fdiv>\n\n    \u003Cdiv class=\"panel\">\n      \u003Cdiv class=\"panel-label\">\u003Cspan class=\"n\">4\u003C\u002Fspan> The code running\u003C\u002Fdiv>\n      \u003Cdiv class=\"code\" id=\"codeDisplay\" aria-live=\"polite\">\u003C\u002Fdiv>\n    \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.cards {\n    display: grid;\n    grid-template-columns: repeat(auto-fill, minmax(52px, 1fr));\n    gap: 6px;\n    min-height: 48px;\n    margin: 10px 0 4px;\n  }\n  .card {\n    background: var(--accent);\n    color: #fff;\n    border-radius: var(--radius-sm);\n    display: flex;\n    align-items: center;\n    justify-content: center;\n    height: 48px;\n    font-family: var(--mono);\n    font-size: .9rem;\n    font-weight: 700;\n    opacity: 0;\n    transform: scale(0.7);\n    transition: opacity .25s, transform .25s;\n  }\n  .card.in { opacity: 1; transform: scale(1); }\n\n  .approach-btns { display: flex; flex-direction: column; gap: 8px; }\n  .approach-btn {\n    display: flex;\n    align-items: center;\n    gap: 10px;\n    padding: 10px 14px;\n    border-radius: var(--radius-sm);\n    border: 2px solid var(--line);\n    background: var(--panel-2);\n    cursor: pointer;\n    font-size: .82rem;\n    text-align: left;\n    transition: border-color .15s, background .15s;\n    width: 100%;\n  }\n  .approach-btn:hover:not(:disabled) { border-color: var(--accent); }\n  .approach-btn:disabled { opacity: .5; cursor: not-allowed; }\n  .approach-btn .tag {\n    font-family: var(--mono);\n    font-size: .7rem;\n    padding: 2px 6px;\n    border-radius: 4px;\n    white-space: nowrap;\n    font-weight: 700;\n  }\n  .tag.good { background: #46d18b22; color: #46d18b; border: 1px solid #46d18b44; }\n  .tag.bad  { background: #ff6b6b22; color: #ff6b6b; border: 1px solid #ff6b6b44; }\n  .tag.warn { background: #f5a62322; color: #f5a623; border: 1px solid #f5a62344; }\n\n  .result-row { display: flex; align-items: baseline; gap: 8px; flex-wrap: wrap; }\n  .result-label { font-size: .72rem; color: var(--muted); font-family: var(--mono); white-space: nowrap; }\n  .result-val { font-family: var(--mono); font-size: .82rem; word-break: break-all; }\n  .result-val.error { color: #ff6b6b; }\n  .result-val.ok { color: #46d18b; }\n\n  .speed-row { display: flex; align-items: center; gap: 12px; margin: 8px 0; flex-wrap: wrap; }","\"use strict\";\nconst $ = id => document.getElementById(id);\n\n\u002F\u002F The async generator source — yields integers with simulated delay.\nasync function* asyncRange(n, delayMs) {\n  for (let i = 1; i \u003C= n; i++) {\n    await new Promise(r => setTimeout(r, delayMs));\n    yield i;\n  }\n}\n\n\u002F\u002F Sliders\n$(\"count\").addEventListener(\"input\", () => { $(\"countOut\").textContent = $(\"count\").value; });\n$(\"delay\").addEventListener(\"input\", () => { $(\"delayOut\").textContent = $(\"delay\").value + \" ms\"; });\n\nconst SNIPPETS = {\n  spread: [\n    '\u003Cspan class=\"tok-kw\">const\u003C\u002Fspan> gen = asyncRange(n, delay);',\n    '',\n    '\u003Cspan class=\"tok-cmt\">\u002F\u002F ❌ async iterables have [Symbol.asyncIterator],\u003C\u002Fspan>',\n    '\u003Cspan class=\"tok-cmt\">\u002F\u002F    not [Symbol.iterator] — spread throws a TypeError\u003C\u002Fspan>',\n    '\u003Cspan class=\"tok-kw\">const\u003C\u002Fspan> result = [\u003Cspan class=\"hl\">...gen\u003C\u002Fspan>];',\n  ],\n  loop: [\n    '\u003Cspan class=\"tok-kw\">const\u003C\u002Fspan> gen = asyncRange(n, delay);',\n    '\u003Cspan class=\"tok-kw\">const\u003C\u002Fspan> result = [];',\n    '',\n    '\u003Cspan class=\"tok-kw\">for await\u003C\u002Fspan> (\u003Cspan class=\"tok-kw\">const\u003C\u002Fspan> item \u003Cspan class=\"tok-kw\">of\u003C\u002Fspan> gen) {',\n    '\u003Cspan class=\"hl\">  result.push(item);\u003C\u002Fspan>',\n    '}',\n    '',\n    '\u003Cspan class=\"tok-cmt\">\u002F\u002F result is now a plain array\u003C\u002Fspan>',\n  ],\n  fromAsync: [\n    '\u003Cspan class=\"tok-kw\">const\u003C\u002Fspan> gen = asyncRange(n, delay);',\n    '',\n    '\u003Cspan class=\"tok-cmt\">\u002F\u002F one awaited call — no loop, no push, no boilerplate\u003C\u002Fspan>',\n    '\u003Cspan class=\"tok-kw\">const\u003C\u002Fspan> result = \u003Cspan class=\"hl\">\u003Cspan class=\"tok-kw\">await\u003C\u002Fspan> Array.fromAsync(gen);\u003C\u002Fspan>',\n  ],\n};\n\nfunction showCode(mode) {\n  $(\"codeDisplay\").innerHTML = SNIPPETS[mode].join(\"\u003Cbr>\");\n}\n\nfunction setStatus(text, kind) {\n  $(\"statusText\").textContent = text;\n  $(\"dot\").className = \"dot \" + kind;\n  $(\"status\").className = \"status \" + kind;\n}\n\nfunction setButtons(disabled) {\n  for (const id of [\"btnSpread\", \"btnLoop\", \"btnFromAsync\"]) {\n    $(id).disabled = disabled;\n  }\n}\n\nfunction addCard(value) {\n  const el = document.createElement(\"div\");\n  el.className = \"card\";\n  el.textContent = value;\n  $(\"cards\").appendChild(el);\n  requestAnimationFrame(() => requestAnimationFrame(() => el.classList.add(\"in\")));\n}\n\nasync function runSpread() {\n  showCode(\"spread\");\n  $(\"cards\").innerHTML = \"\";\n  $(\"resultVal\").textContent = \"—\";\n  $(\"resultVal\").className = \"result-val\";\n  $(\"timeVal\").textContent = \"—\";\n  setButtons(true);\n  setStatus(\"Trying spread…\", \"warn\");\n\n  await new Promise(r => setTimeout(r, 50));\n\n  try {\n    const gen = asyncRange(+$(\"count\").value, +$(\"delay\").value);\n    const result = [...gen]; \u002F\u002F will throw\n    $(\"resultVal\").textContent = JSON.stringify(result);\n  } catch (err) {\n    setStatus(\"TypeError thrown — spread doesn't work on async iterables.\", \"bad\");\n    $(\"resultVal\").className = \"result-val error\";\n    $(\"resultVal\").textContent = String(err);\n    $(\"timeVal\").textContent = \"\u003C 1 ms (fails synchronously before any items are pulled)\";\n  }\n\n  setButtons(false);\n}\n\nasync function runLoop() {\n  showCode(\"loop\");\n  $(\"cards\").innerHTML = \"\";\n  $(\"resultVal\").textContent = \"—\";\n  $(\"resultVal\").className = \"result-val\";\n  $(\"timeVal\").textContent = \"—\";\n  setButtons(true);\n  setStatus(\"Collecting with for-await…\", \"info\");\n\n  const n = +$(\"count\").value;\n  const delay = +$(\"delay\").value;\n  const t0 = performance.now();\n\n  const result = [];\n  for await (const item of asyncRange(n, delay)) {\n    result.push(item);\n    addCard(item);\n    setStatus(`Collected ${result.length} of ${n}…`, \"info\");\n  }\n\n  const elapsed = Math.round(performance.now() - t0);\n  setStatus(`Done — collected ${result.length} items.`, \"good\");\n  $(\"resultVal\").className = \"result-val ok\";\n  $(\"resultVal\").textContent = JSON.stringify(result);\n  $(\"timeVal\").textContent = `${elapsed} ms (~${delay} ms × ${n} items)`;\n  setButtons(false);\n}\n\nasync function runFromAsync() {\n  showCode(\"fromAsync\");\n  $(\"cards\").innerHTML = \"\";\n  $(\"resultVal\").textContent = \"—\";\n  $(\"resultVal\").className = \"result-val\";\n  $(\"timeVal\").textContent = \"—\";\n  setButtons(true);\n  setStatus(\"Collecting with Array.fromAsync…\", \"info\");\n\n  const n = +$(\"count\").value;\n  const delay = +$(\"delay\").value;\n\n  \u002F\u002F Use a generator that also fires the visual update per item.\n  async function* visualRange(count, ms) {\n    let seen = 0;\n    for await (const v of asyncRange(count, ms)) {\n      yield v;\n      seen++;\n      addCard(v);\n      setStatus(`Collected ${seen} of ${count}…`, \"info\");\n    }\n  }\n\n  const supported = typeof Array.fromAsync === \"function\";\n  if (!supported) {\n    setStatus(\"Array.fromAsync not in this browser — running the polyfill instead.\", \"warn\");\n  }\n\n  const fromAsync = typeof Array.fromAsync === \"function\"\n    ? Array.fromAsync.bind(Array)\n    : async (iter) => { const a = []; for await (const v of iter) a.push(v); return a; };\n\n  const t0 = performance.now();\n  const result = await fromAsync(visualRange(n, delay));\n  const elapsed = Math.round(performance.now() - t0);\n\n  setStatus(`Done — collected ${result.length} items.`, \"good\");\n  $(\"resultVal\").className = \"result-val ok\";\n  $(\"resultVal\").textContent = JSON.stringify(result);\n  $(\"timeVal\").textContent = `${elapsed} ms (~${delay} ms × ${n} items)`;\n  setButtons(false);\n}\n\n$(\"btnSpread\").addEventListener(\"click\", runSpread);\n$(\"btnLoop\").addEventListener(\"click\", runLoop);\n$(\"btnFromAsync\").addEventListener(\"click\", runFromAsync);\n\n\u002F\u002F Start with fromAsync code visible\nshowCode(\"fromAsync\");\nsetStatus(\"Pick an approach above.\", \"info\");",{"height":40,"autorun":17},520,{"slug":33,"title":42,"excerpt":43,"coverUrl":44},"You're collecting async iterable results with a for-await loop. `Array.fromAsync` does it in one call.","A for-await loop that pushes into an array, or the `await Promise.all([...asyncIterable])` workaround that silently fails — `Array.fromAsync` replaces both with a single awaited call. It's Baseline 2024.","\u002Fmedia\u002Fcovers\u002Farray-from-async-async-iterable.png"]