Request Cache

<script>
  import { highlightCode } from '../../lib/highlight.server';
  import { files } from './files.ts';
  import { overview, topWords, themes, extremes, richness } from './analyzeBook.ts';

  const sources = await loadSources(files);

  // Five independent consumers of the same book. Each helper wraps the memoized
  // analysis, so these five calls parse the 124k-word text exactly once between
  // them — the first is a cache miss, the rest are hits.
  const facetOverview = overview();
  const facetTopWords = topWords();
  const facetThemes = themes();
  const facetExtremes = extremes();
  const facetHapax = richness();

  const nf = new Intl.NumberFormat('en-US');
  const topMax = facetTopWords[0]?.[1] ?? 1;

  // Each panel's snippet shows the real pipeline: one memoized analysis at module
  // scope, then this panel pulling its slice out of the shared result.
  const snip = (pick) => highlightCode(`// parsed once per request, shared across panels\nconst analyzeCached = requestMemo(() => analyze(BOOK));\n${pick}`, 'ts');
  const codeOverview = await snip('const { words, unique, sentences } = analyzeCached();');
  const codeTopWords = await snip('const { topWords } = analyzeCached();');
  const codeThemes = await snip('const { themes } = analyzeCached();');
  const codeExtremes = await snip('const { longestWord, longestSentenceExcerpt } = analyzeCached();');
  const codeRichness = await snip('const { hapax } = analyzeCached();');
</script>

<div class="stack">
  <p class="hint">
    Each panel calls its own helper, but they all share one memoized analysis — a single parse per request, so one miss and four hits. Open the
    <strong>debug bar</strong> (bottom right) and its <strong>Cache</strong> tab to check the stats.
  </p>

  <div class="facets">
    <section class="facet">
      <h3>Overview</h3>
      <dl class="stats">
        <div>
          <dt>Words</dt>
          <dd>{nf.format(facetOverview.words)}</dd>
        </div>
        <div>
          <dt>Unique</dt>
          <dd>{nf.format(facetOverview.unique)}</dd>
        </div>
        <div>
          <dt>Sentences</dt>
          <dd>{nf.format(facetOverview.sentences)}</dd>
        </div>
        <div>
          <dt>Reading time</dt>
          <dd>~{facetOverview.readingMinutes} min</dd>
        </div>
      </dl>
      <!-- eslint-disable-next-line svelte/no-at-html-tags -->
      <div class="snippet">{@html codeOverview}</div>
    </section>

    <section class="facet">
      <h3>Top words</h3>
      <ul class="bars">
        {#each facetTopWords as [word, count] (word)}
          <li>
            <span class="bar-word">{word}</span>
            <span class="bar-track"><span class="bar-fill" style:width="{(count / topMax) * 100}%"></span></span>
            <span class="bar-count">{nf.format(count)}</span>
          </li>
        {/each}
      </ul>
      <!-- eslint-disable-next-line svelte/no-at-html-tags -->
      <div class="snippet">{@html codeTopWords}</div>
    </section>

    <section class="facet">
      <h3>Themes</h3>
      <ul class="chips">
        {#each facetThemes as [word, count] (word)}
          <li><span class="chip-word">{word}</span><span class="chip-count">{nf.format(count)}</span></li>
        {/each}
      </ul>
      <!-- eslint-disable-next-line svelte/no-at-html-tags -->
      <div class="snippet">{@html codeThemes}</div>
    </section>

    <section class="facet">
      <h3>Extremes</h3>
      <p class="extreme-label">Longest word</p>
      <p class="extreme-value"><code>{facetExtremes.longestWord}</code></p>
      <p class="extreme-label">Longest sentence · {facetExtremes.longestSentenceWords} words</p>
      <blockquote>{facetExtremes.longestSentenceExcerpt.slice(0, 260)}…</blockquote>
      <!-- eslint-disable-next-line svelte/no-at-html-tags -->
      <div class="snippet">{@html codeExtremes}</div>
    </section>

    <section class="facet">
      <h3>Vocabulary richness</h3>
      <p class="hapax"><strong>{nf.format(facetHapax)}</strong> words appear exactly once</p>
      <p class="extreme-label">Hapax legomena — {Math.round((facetHapax / facetOverview.unique) * 100)}% of the vocabulary</p>
      <!-- eslint-disable-next-line svelte/no-at-html-tags -->
      <div class="snippet">{@html codeRichness}</div>
    </section>
  </div>
</div>