From 058da3f101c80120962f8b12e803367e2c9441dd Mon Sep 17 00:00:00 2001
From: Dan Smith <dev@dotherightthing.co.nz>
Date: Wed, 30 Dec 2020 16:42:49 +1300
Subject: [PATCH] Prepend anchor IDs with a string to prevent them from
 starting with a number

---
 src/class-wpdtrt-anchorlinks-plugin.php | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/class-wpdtrt-anchorlinks-plugin.php b/src/class-wpdtrt-anchorlinks-plugin.php
index cea4bdd..0cbbf72 100644
--- a/src/class-wpdtrt-anchorlinks-plugin.php
+++ b/src/class-wpdtrt-anchorlinks-plugin.php
@@ -157,7 +157,7 @@ public function render_headings_as_anchors( string $content ) : string {
 
 			// class is also used by $this->render_headings_in_sections().
 			$heading->setAttribute( 'class', 'wpdtrt-anchorlinks__anchor' );
-			$heading_id = sanitize_title( $heading->nodeValue ); // phpcs:ignore
+			$heading_id = 'section-' . sanitize_title( $heading->nodeValue ); // phpcs:ignore
 			$heading->setAttribute( 'id', $heading_id );
 			$heading->setAttribute( 'tabindex', '-1' );