init

.gitignore

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+node_modules/
+package-lock.json
+.DS_Store

.npmignore

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+test/
+tmp/
+.travis.yml
+.github/
+.DS_Store

README.md

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 # hexo-filter-mathjax
-Pre-render MathJax
+
+Pre-render MathJax into svg using [mathjax-node].
+
+## Installation
+
+``` bash
+$ npm install hexo-filter-mathjax --save
+```
+
+## Options
+
+You can configure this plugin in `_config.yml`.
+
+``` yaml
+mathjax:
+  inlineQuote: ['\$', '\$']
+  blockQuote: ['\$\$', '\$\$']
+  MathJax:
+    SVG:
+      font: Gyre-Pagella
+```
+
+- **inlineQuote** - Similar to `MathJax.inlineMath`, but only support one pair.
+- **blockQuote** - Similar to `MathJax.blockMath`, but only support one pair.
+- **MathJax** - MathJax configuration, see [svg processor][svg-processor].
+
+## License
+
+Licensed under [MIT](LICENSE).
+
+[mathjax-node]: https://github.com/mathjax/MathJax-node
+[svg-processor]: http://docs.mathjax.org/en/latest/options/output-processors/SVG.html#the-svg-output-processor

index.js

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+/* global hexo */
+
+'use strict';
+
+const mathjax = require('./lib/mathjax');
+
+mathjax.config(hexo.config.mathjax);
+
+hexo.extend.filter.register('before_post_render', mathjax.beforeRender);
+hexo.extend.filter.register('after_post_render', mathjax.render);

lib/mathjax.js

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+const mathJax = require("mathjax-node");
+const crypto = require('crypto');
+const getMarker = getUid('MATHJAX');
+const mathList = [];
+
+let inline_mathjax_regex, block_mathjax_regex;
+
+// markdown is easier to handle
+exports.beforeRender = function (data) {
+  data.content = data.content
+    .replace(block_mathjax_regex, function (a, math) {
+      const marker = getMarker();
+      mathList.push({ math, block: true, marker });
+      return marker;
+    })
+    .replace(inline_mathjax_regex, function (a, math) {
+      const marker = getMarker();
+      mathList.push({ math, marker });
+      return marker;
+    });
+
+  return data;
+}
+
+exports.render = function (data) {
+  if (!mathList.length) return data;
+
+  let { content } = data;
+
+  return render();
+
+  function render() {
+    const { math, marker, block } = mathList.shift();
+    return mathJax.typeset({ math, format: 'TeX', svg: true, })
+      .then(res => {
+        if (!res.errors) {
+          if (block)
+            content = content.replace(new RegExp('<p>\\s*' + marker), '<p style="text-align:center">' + res.svg);
+          else
+            content = content.replace(marker, res.svg);
+
+          if (mathList.length) return render();
+
+          data.content = content;
+          return data;
+        }
+
+        throw res.errors;
+      });
+  }
+}
+
+exports.config = function (config) {
+  config = config || {};
+
+  const inlineQuote = parseTag(config.inlineQuote, '\\$');
+  const blockQuote = parseTag(config.blockQuote, '\\$\\$');
+
+  inline_mathjax_regex = new RegExp(`${inlineQuote[0]}(.+?)${inlineQuote[1]}`, 'g');
+  block_mathjax_regex = new RegExp(`${blockQuote[0]}\\s*(.+?)\\s*${blockQuote[1]}`, 'g');
+
+  // TODO:
+  delete config.inlineQuote;
+  delete config.blockQuote;
+  mathJax.config(config);
+}
+
+function getUid(ns) {
+  const hash = crypto.createHash('md5').update(String(Date.now())).digest('hex').substring(0, 6).toUpperCase();
+  let i = 0;
+  return () => [ns, hash, i++].join('-');
+}
+
+function parseTag(input, defaultTag) {
+  if (typeof input === 'string') {
+    const tag = input || defaultTag;
+    input = [tag, tag];
+  }
+
+  else if (!Array.isArray(input)) {
+    input = [defaultTag, defaultTag];
+  }
+
+  else {
+    const tag = input[0] || input[1] || defaultTag;
+    input = [tag, input[1] || tag];
+  }
+
+  return input;
+}

package.json

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+{
+  "name": "hexo-filter-mathjax",
+  "version": "0.1.0",
+  "description": "Pre-render MathJax",
+  "main": "index.js",
+  "repository": {
+    "type": "git",
+    "url": "git+https://github.com/ike-c/hexo-filter-mathjax.git"
+  },
+  "keywords": [
+    "hexo",
+    "mathjax",
+    "prerender",
+    "mathjax-node",
+    "hexo-filter"
+  ],
+  "author": "ike-c <9206414+ike-c@users.noreply.github.com>",
+  "license": "MIT",
+  "bugs": {
+    "url": "https://github.com/ike-c/hexo-filter-mathjax/issues"
+  },
+  "homepage": "https://github.com/ike-c/hexo-filter-mathjax#readme",
+  "dependencies": {
+    "mathjax-node": "^2.1.1"
+  }
+}