Add mathjax js loading filter

Author: jiwonac

.eleventy.js

@@ -110,6 +110,14 @@ module.exports = function(eleventyConfig) {
         return (lastSpace > 0 ? truncated.substring(0, lastSpace) : truncated) + "...";
     });
 
+    /* Math detection filter: checks for LaTeX/MathJax delimiters */
+    eleventyConfig.addFilter("hasMath", (content) => {
+        if (!content) return false;
+        // Detect: $...$ (inline), $$...$$ (display), \(...\), \[...\]
+        const mathPattern = /\$\$[\s\S]+?\$\$|\$[^\$\n]+?\$|\\\([\s\S]+?\\\)|\\\[[\s\S]+?\\\]/;
+        return mathPattern.test(content);
+    });
+
     /* Set directories */
     return {
         dir: {

src/_includes/_head.html

@@ -63,11 +63,9 @@
     <!-- Favicon -->
     <link rel="icon" href="/favicon.ico">
 
-    <!--mathjax-->
-    <script type="text/javascript" id="MathJax-script" async
-            src="https://cdn.jsdelivr.net/npm/mathjax@3/es5/tex-mml-chtml.js">
-    </script>
-    <!--use dollar signs for math-->
+    <!-- MathJax: only load on pages with math content -->
+    {% assign needsMath = content | hasMath %}
+    {% if needsMath %}
     <script>
         MathJax = {
             tex: {
@@ -76,6 +74,8 @@
             }
         };
     </script>
+    <script async src="https://cdn.jsdelivr.net/npm/mathjax@3/es5/tex-mml-chtml.js"></script>
+    {% endif %}
 
     <!-- JSON-LD Structured Data -->
     <script type="application/ld+json">