MathJax support

src/config.default.json

@@ -7,7 +7,8 @@
   "modules": {
     "rss": true,
     "webhook": true,
-    "prism": true
+    "prism": true,
+    "mathjax": true
   },
   "home": {
     "index": "index.ejs",
@@ -42,5 +43,9 @@
     "tasklists": true,
     "openLinksInNewWindow": true,
     "emoji": true
+  },
+  "mathjax": {
+    "output_format": "svg",
+    "speak_text": true
   }
 }

src/renderer.js

@@ -1,35 +1,99 @@
 const fs = require('fs');
 const showdown = require('showdown');
-const Prism = require('node-prismjs');
 
 module.exports = (config) => {
   const converter = new showdown.Converter(config['showdown']);
+
+  const renderShowDown = (data, cb) => {
+    const html = converter.makeHtml(data);
+    cb(html);
+  };
+
+  let Prism;
+  if (config['modules']['prism'])
+    Prism = require('node-prismjs');
+
+  const renderPrism = (data, cb) => {
+    if (!config['modules']['prism'])
+      return cb(data);
+    const codeRegex = /```([\w-]+)\r?\n((?:(?!```)[\s\S])*)\r?\n```/m;
+    let match;
+    while ((match = codeRegex.exec(data))) {
+      const lang = match[1].trim();
+      const code = match[2].trim();
+      try {
+        const block = Prism.highlight(code, Prism.languages[lang] || Prism.languages.autoit, lang);
+        data = data.slice(0, match.index) + `<pre><code class="${lang} language-${lang}">` + block + '</code></pre>' + data.slice(match.index + match[0].length);
+      } catch (err) {
+        console.error(err);
+      }
+    }
+    cb(data);
+  };
+
+  let mjAPI;
+  if (config['modules']['mathjax']) {
+    mjAPI = require('mathjax-node');
+    mjAPI.config({
+      MathJax: {
+        tex2jax: {
+          inlineMath: [['$', '$']],
+          displayMath: [['$$', '$$']]
+        }
+      }
+    });
+  }
+
+  const renderMathJax = (data, cb) => {
+    if (!config['modules']['mathjax'])
+      return cb(data);
+
+    const doMJ = (match, format) => {
+      const eq = match[1].trim();
+      const output = config['mathjax']['output_format'];
+      const mjConf = {
+        math: eq,
+        format: format,
+        speakText: config['mathjax']['speak_text']
+      };
+      mjConf[output] = true;
+      mjAPI.typeset(mjConf, (res) => {
+        data = data.slice(0, match.index) + res[output] + data.slice(match.index + match[0].length);
+        renderMathJax(data, (data2) => {
+          cb(data2);
+        });
+      });
+    };
+
+    const eqRegex = /\$\$((?:(?!\$\$)[\s\S])*)\$\$/m;
+    const inlineEqRegex = /\$([^$]*)\$/;
+
+    let match;
+    if ((match = eqRegex.exec(data))) {
+      doMJ(match, 'TeX');
+    } else if ((match = inlineEqRegex.exec(data))) {
+      doMJ(match, 'inline-TeX');
+    } else {
+      cb(data);
+    }
+  };
+
   return {
+    renderShowDown: config['test'] ? renderShowDown : undefined,
+    renderPrism: config['test'] ? renderPrism : undefined,
+    renderMathJax: config['test'] ? renderMathJax : undefined,
     render: (file, cb) => {
       fs.readFile(file, {encoding: 'UTF-8'}, (err, data) => {
         if (err)
           return cb(err);
 
-        if (config['modules']['prism']) {
-          const codeRegex = /```([\w-]+)\r?\n((?:(?!```)[\s\S])*)\r?\n```/m;
-          let match;
-          while ((match = codeRegex.exec(data))) {
-            const lang = match[1].trim();
-            const code = match[2].trim();
-            try {
-              const block = Prism.highlight(code, Prism.languages[lang] || Prism.languages.autoit, lang);
-              data = data.slice(0, match.index) + `<pre><code class="${lang} language-${lang}">` + block + '</code></pre>' + data.slice(match.index + match[0].length);
-            } catch (err) {
-              console.error(err);
-            }
-          }
-        }
-
-
-        const html = converter.makeHtml(data);
-
-
-        cb(null, html);
+        renderPrism(data, (data2) => {
+          renderMathJax(data2, (data3) => {
+            renderShowDown(data3, (html) => {
+              cb(null, html);
+            });
+          });
+        });
       });
     }
   };