From 1336e51c402f0da078581a826b8fe848206aa91e Mon Sep 17 00:00:00 2001
From: John Factotum <50942278+johnfactotum@users.noreply.github.com>
Date: Thu, 16 Dec 2021 15:11:55 +0800
Subject: [PATCH] Allow `span` in toc nav items

According to https://www.w3.org/publishing/epub32/epub-packages.html#sec-package-nav-def-model:

"A child `a` element describes the target that the link points to, while a `span` element serves as a heading for breaking down lists into distinct groups (for example, a large list of illustrations can be segmented into several lists, one for each chapter)."
---
 src/navigation.js | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/navigation.js b/src/navigation.js
index 8d593a8..801598b 100644
--- a/src/navigation.js
+++ b/src/navigation.js
@@ -191,7 +191,8 @@ class Navigation {
 	 */
 	navItem(item, parent) {
 		let id = item.getAttribute("id") || undefined;
-		let content = filterChildren(item, "a", true);
+		let content = filterChildren(item, "a", true)
+			|| filterChildren(item, "span", true);
 
 		if (!content) {
 			return;