VirtualList

import { useRef, useState } from "react";
import { Button, VirtualList, type Virtualizer } from "cennge-ui";

interface Page {
  number: number;
  error?: string;
}

// A run of playwright-msi-scraper over 6,000 pages; a few of them timed out.
const pages: Page[] = Array.from({ length: 6_000 }, (_, index) => ({
  number: index + 1,
  error: index % 1_237 === 611 ? "Timeout 30000ms exceeded" : undefined,
}));

const failures = pages.flatMap((page, index) => (page.error ? [index] : []));

export default function NextFailure() {
  const list = useRef<Pick<Virtualizer, "scrollToIndex">>(null);
  const [current, setCurrent] = useState(-1);

  const go = (step: 1 | -1) => {
    const next = current < 0 && step < 0 ? failures.length - 1 : (current + step + failures.length) % failures.length;
    setCurrent(next);
    // "auto" scrolls only as far as it takes to bring the row into view.
    list.current?.scrollToIndex(failures[next]!, { align: "auto" });
  };

  return (
    <div className="flex w-full flex-col gap-3">
      <div className="flex flex-wrap items-center gap-2">
        <Button size="sm" variant="flat" onClick={() => go(-1)}>
          Previous failure
        </Button>
        <Button size="sm" variant="flat" color="danger" onClick={() => go(1)}>
          Next failure
        </Button>
        <span className="text-sm text-muted" aria-live="polite">
          {current < 0 ? `${failures.length} of 6,000 pages failed` : `Failure ${current + 1} of ${failures.length}`}
        </span>
      </div>
      <VirtualList
        items={pages}
        getKey={(page) => page.number}
        estimateSize={30}
        listRef={list}
        aria-label="Scraped pages"
        className="h-64 w-full rounded-large bg-surface-3"
      >
        {(page, index) => (
          <div
            className={`flex gap-4 px-4 py-1.5 font-mono text-xs ${index === failures[current] ? "bg-danger-bg" : ""}`}
          >
            <span className="w-20 shrink-0 tabular-nums">page {page.number}</span>
            {page.error ? <span className="text-danger-text">{page.error}</span> : <span className="text-muted">saved</span>}
          </div>
        )}
      </VirtualList>
    </div>
  );
}

import { VirtualList } from "cennge-ui";

type Row =
  | { kind: "day"; label: string }
  | { kind: "deploy"; repository: string; environment: "production" | "preview"; time: string };

const repositories = ["cennge-ui", "ai-niche-scout", "payload-cache", "spredo-crypto-screener", "playwright-msi-scraper"];
const dayName = new Intl.DateTimeFormat("en-US", { weekday: "long", month: "long", day: "numeric", year: "numeric", timeZone: "UTC" });

// A year of deploys, newest first, each day under a heading row.
const rows: Row[] = Array.from({ length: 365 }, (_, dayIndex): Row[] => [
  { kind: "day", label: dayName.format(Date.UTC(2026, 10, 8 - dayIndex)) },
  ...Array.from({ length: 3 + (dayIndex % 4) }, (_, n): Row => ({
    kind: "deploy",
    repository: repositories[(dayIndex + n) % repositories.length]!,
    environment: (dayIndex + n) % 3 ? "preview" : "production",
    time: `${String(20 - n * 3).padStart(2, "0")}:${String((dayIndex * 7 + n * 13) % 60).padStart(2, "0")}`,
  })),
]).flat();

export default function DeploysByDay() {
  return (
    <VirtualList
      items={rows}
      estimateSize={(index) => (rows[index]?.kind === "day" ? 34 : 40)}
      aria-label="Deploys by day"
      className="h-80 w-full max-w-md rounded-large bg-surface-3"
    >
      {(row) =>
        row.kind === "day" ? (
          <p className="px-4 pt-3 pb-1.5 text-xs font-semibold text-muted">{row.label}</p>
        ) : (
          <div className="flex items-center gap-3 px-4 py-2 text-sm">
            <span className="min-w-0 flex-1 truncate font-medium">{row.repository}</span>
            <span className={row.environment === "production" ? "text-xs text-success-text" : "text-xs text-muted"}>
              {row.environment}
            </span>
            <span className="w-11 text-right text-muted tabular-nums">{row.time}</span>
          </div>
        )
      }
    </VirtualList>
  );
}

import { useState } from "react";
import { useVirtualizer } from "cennge-ui";

const paths = ["/api/posts", "/api/posts?page=2", "/api/media/cover.webp", "/api/users/me", "/api/globals/footer"];

// 20,000 lines of payload-cache's request log.
const lines = Array.from({ length: 20_000 }, (_, index) => {
  const seconds = index * 0.37;
  const time = new Date(Date.UTC(2026, 10, 8, 9) + seconds * 1000).toISOString().slice(11, 23);
  const hit = index % 5 !== 0;
  return `${time}  ${hit ? "HIT " : "MISS"}  ${paths[index % paths.length]}  ${hit ? 2 + (index % 4) : 40 + (index % 90)} ms`;
});

export default function RequestLog() {
  const [scrollElement, setScrollElement] = useState<HTMLDivElement | null>(null);
  const virtualizer = useVirtualizer({ count: lines.length, estimateSize: 20, scrollElement, paddingStart: 8, paddingEnd: 8 });

  return (
    <div
      ref={setScrollElement}
      tabIndex={0}
      role="region"
      aria-label="Request log"
      className="h-72 w-full overflow-auto rounded-large bg-surface-1 font-mono text-xs leading-5 outline-none focus-visible:outline-2 focus-visible:outline-solid focus-visible:outline-ring"
    >
      <div style={{ position: "relative", height: virtualizer.totalSize }}>
        {virtualizer.items.map(({ index, start }) => (
          <div
            key={index}
            ref={virtualizer.measureElement}
            data-index={index}
            className="flex gap-4 px-4"
            style={{ position: "absolute", top: 0, left: 0, width: "100%", transform: `translateY(${start}px)` }}
          >
            <span className="w-10 shrink-0 text-right text-muted select-none">{index + 1}</span>
            <span className="min-w-0 break-words whitespace-pre-wrap">{lines[index]}</span>
          </div>
        ))}
      </div>
    </div>
  );
}