Generate a two-level TOC for the epub file

Issue marijnh#381

Author: marijnh

.gitignore

@@ -27,5 +27,6 @@
 /epub/hints.xhtml
 /epub/img/*
 /epub/content.opf
+/epub/toc.xhtml
 /book.epub
 /book.mobi

Makefile

@@ -65,7 +65,10 @@ book.epub: epub/titlepage.xhtml epub/toc.xhtml epub/hints.xhtml $(foreach CHAP,$
 	grep '<img' epub/*.xhtml | sed -e 's/.*src="\([^"]*\)".*/\1/' | xargs -I{} cp --parents "{}" epub
 	node src/add_images_to_epub.js
 	cd epub; zip -X ../$@ mimetype
-	cd epub; zip -X ../$@ -r * -x mimetype -x content.opf.src
+	cd epub; zip -X ../$@ -r * -x mimetype -x *.src
+
+epub/toc.xhtml: epub/toc.xhtml.src $(foreach CHAP,$(CHAPTERS),epub/$(CHAP).xhtml) epub/hints.xhtml
+	node src/generate_epub_toc.js $^ > $@
 
 epub/%.xhtml: %.md src/render_html.js
 	node src/render_html.js --epub $< > $@

epub/toc.xhtml renamed to epub/toc.xhtml.src

@@ -75,29 +75,7 @@
     <!-- machine-readable TOC -->
     <nav xmlns:epub="http://www.idpf.org/2007/ops" epub:type="toc" id="toc">
       <ol>
-        <li><a href="00_intro.xhtml">Introduction</a></li>
-        <li><a href="01_values.xhtml">Values, Types, and Operators</a></li>
-        <li><a href="02_program_structure.xhtml">Program Structure</a></li>
-        <li><a href="03_functions.xhtml">Functions</a></li>
-        <li><a href="04_data.xhtml">Data Structures: Objects and Arrays</a></li>
-        <li><a href="05_higher_order.xhtml">Higher-order Functions</a></li>
-        <li><a href="06_object.xhtml">The Secret Life of Objects</a></li>
-        <li><a href="07_robot.xhtml">Project: A Robot</a></li>
-        <li><a href="08_error.xhtml">Bugs and Errors</a></li>
-        <li><a href="09_regexp.xhtml">Regular Expressions</a></li>
-        <li><a href="10_modules.xhtml">Modules</a></li>
-        <li><a href="11_async.xhtml">Asynchronous Programming</a></li>
-        <li><a href="12_language.xhtml">Project: A Programming Language</a></li>
-        <li><a href="13_browser.xhtml">JavaScript and the Browser</a></li>
-        <li><a href="14_dom.xhtml">The Document Object Model</a></li>
-        <li><a href="15_event.xhtml">Handling Events</a></li>
-        <li><a href="16_game.xhtml">Project: A Platform Game</a></li>
-        <li><a href="17_canvas.xhtml">Drawing on Canvas</a></li>
-        <li><a href="18_http.xhtml">HTTP and Forms</a></li>
-        <li><a href="19_paint.xhtml">Project: A Pixel Art Editor</a></li>
-        <li><a href="20_node.xhtml">Node.js</a></li>
-        <li><a href="21_skillsharing.xhtml">Project: Skill-Sharing Website</a></li>
-        <li><a href="hints.xhtml">Hints to the exercises</a></li>
+{{full_toc}}
       </ol>
     </nav>
   </body>

src/generate_epub_toc.js

@@ -0,0 +1,25 @@
+const {readFileSync} = require("fs")
+const {basename} = require("path")
+
+let [template, ...chapters] = process.argv.slice(2)
+
+function esc(str) {
+  return str.replace(/[<>&"]/g, ch => ch == "<" ? "&lt;" : ch == ">" ? "&gt;" : ch == "&" ? "&amp;" : "&quot;")
+}
+
+let toc = ""
+const section = /<h2\b[^>]*><a [^>]*?id="(h_.*?)".*?><\/a>(.*?)<\/h2>/g
+
+for (let chapter of chapters) {
+  let text = readFileSync(chapter, "utf8")
+  let base = basename(chapter)
+  let title = /<h1.*?>(.*?)<\/h1>/.exec(text)[1]
+  toc += `        <li><a href="${base}">${esc(title)}</a>
+          <ol>\n`
+  for (let match; match = section.exec(text);)
+    toc += `            <li><a href="${base}#${match[1]}">${esc(match[2])}</a></li>\n`
+  toc += `         </ol>
+        </li>\n`
+}
+
+console.log(readFileSync(template, "utf8").replace("{{full_toc}}", toc))