Summary

• Add prettyUrls config option (book.json) that strips .html extensions from generated links, enabling clean URLs (e.g., href="guide" instead of href="guide.html") for static hosting like GitHub Pages
• Output files remain as page.html — only the URLs in links are affected. GitHub Pages natively serves page.html when /page is requested, so no directory rewriting is needed
• Root-level boolean config key — not nested under output — because the legacy plugin API (decodeConfig) reserves and deletes values.output for deprecated output folder path compatibility

How it works

Two URL rewriting rules in fileToURL.ts, applied in order:

1. directoryIndex (existing) — README.md → index.html → ./ and subdir/README.md → subdir/index.html → subdir/. This rule is unchanged and fires first for any index.html output
2. prettyUrls (new) — all other .html URLs get the extension stripped: page.html → page, subdir/page.html → subdir/page

Output files are unaffected — fileToOutput.ts still produces page.html. Only the link URLs in generated HTML change.

URL mapping

Usage

{
  "prettyUrls": true
}

Test plan

• Unit tests for fileToOutput (8 tests) — output filenames unchanged in both modes
• Unit tests for fileToURL (8 tests) — default mode produces .html URLs, prettyUrls mode produces extensionless URLs; directoryIndex conversion preserved in both modes
• Integration snapshot test — builds a fixture book with prettyUrls: true, verifies guide.html exists and links contain href="guide" (not href="guide.html")
• Full test suite passes (259 tests)

Closes #496

🤖 Generated with Claude Code