Function lintDuplicateAudioTracks

packages/lint/src/project.ts:464–513

(htmlSources: HtmlSource[])

}

function lintDuplicateAudioTracks(htmlSources: HtmlSource[]): HyperframeLintFinding[] {
  const findings: HyperframeLintFinding[] = [];
  function extractAttr(tag: string, name: string): string | null {
    const re = new RegExp(`\\b${name}\\s*=\\s*["']([^"']+)["']`, "i");
    const m = tag.match(re);
    return m?.[1] ?? null;
  }

  const tracks: Array<{ trackIndex: number; start: number; end: number; src: string }> = [];
  const seen = new Set<string>();

  for (const { html } of htmlSources) {
    const audioTagRe = /<audio\b[^>]*>/gi;
    let match: RegExpExecArray | null;
    while ((match = audioTagRe.exec(html)) !== null) {
      const tag = match[0];
      const trackStr = extractAttr(tag, "data-track-index");
      const startStr = extractAttr(tag, "data-start");
      const durStr = extractAttr(tag, "data-duration");
      const src = extractAttr(tag, "src") ?? "unknown";
      if (!trackStr || !startStr) continue;

      const trackIndex = parseInt(trackStr, 10);
      const start = parseFloat(startStr);
      const duration = durStr ? parseFloat(durStr) : Infinity;
      const key = `${src}:${start}:${duration}:${trackIndex}`;
      if (seen.has(key)) continue;
      seen.add(key);

      tracks.push({ trackIndex, start, end: start + duration, src });
    }
  }

  for (let i = 0; i < tracks.length; i++) {
    for (let j = i + 1; j < tracks.length; j++) {
      const a = tracks[i]!;
      const b = tracks[j]!;
      if (a.trackIndex !== b.trackIndex) continue;
      if (a.start < b.end && b.start < a.end) {
        findings.push({
          code: "duplicate_audio_track",
          severity: "warning",
          message: `Multiple <audio> elements on track ${a.trackIndex} overlap (${a.src} at ${a.start}-${Number.isFinite(a.end) ? a.end.toFixed(1) : "end"}s, ${b.src} at ${b.start}-${Number.isFinite(b.end) ? b.end.toFixed(1) : "end"}s). This causes layered audio playback.`,
          fixHint: "Use non-overlapping time windows or different track indices.",
        });
      }
    }
  }
  return findings;
}

/**
 * Error if a `data-composition-src` reference points at a file that is