MathJax 2 vs. 3 hack

gistfile1.txt

{% if page.mathjax3 %} 

<script>
window.MathJax = {
  options: {
    menuOptions: {
      settings: {
        zoom: "None",
        zscale: "150%"
      }
    },

    renderActions: {
      findScript: [10, function (doc) {
        for (const node of document.querySelectorAll('script[type^="math/tex"]')) {
          const display = !!node.type.match(/; *mode=display/);
          const math = new doc.options.MathItem(node.textContent, doc.inputJax[0], display);
          const text = document.createTextNode('');
          node.parentNode.replaceChild(text, node);
          math.start = {node: text, delim: '', n: 0};
          math.end = {node: text, delim: '', n: 0};
          doc.math.push(math);
        }
      }, '']
    },
      
    ignoreHtmlClass: 'tex2jax_ignore',
    processHtmlClass: 'tex2jax_process'
  },
  tex: {
    inlineMath: [['$','$']],
    displayMath: [['$$','$$']],
    processEnvironments: false,
    tags: "ams",
    macros: {
      abs: ['\\left\\lvert #2 \\right\\rvert_{\\text{#1}}', 2, ""],
      abracket: ['{\\langle #1 \\rangle}', 1],
      pbracket: ['{\\bigl #1 \\bigr}', 1],
      bvec: ['{\\lgroup #1 \\rgroup}', 1],
      func: ['{#1 \\left( #2 \\right)}', 2]
    },
    autoload: {
      color: [],
      colorV2: ['color']
    },
    packages: {'[+]': ['noerrors']}
  },
  loader: {
    load: ['[tex]/noerrors']
  }
};
</script>
<script src="https://cdn.jsdelivr.net/npm/mathjax@3/es5/tex-mml-chtml.js" id="MathJax-script"></script>

{% else %}
  <script src="https://cdnjs.cloudflare.com/ajax/libs/mathjax/2.7.0/MathJax.js?config=TeX-AMS-MML_HTMLorMML" type="text/javascript"></script> 

  <script type="text/x-mathjax-config">
  MathJax.Hub.Config({
    showProcessingMessages: false,
    messageStyle: 'none',

    tex2jax: {
      inlineMath: [['$','$']],
      displayMath: [['$$','$$']],
      processEnvironments: false
    },

   TeX: {
      displayAlign: "left",
       
      // show equation numbers
      equationNumbers: {
        autoNumber: "AMS"
     },

      Macros: {
        abs:      ['\\left\\lvert #2 \\right\\rvert_{\\text{#1}}', 2, ""],
        abracket: ['{\\langle #1 \\rangle}', 1],
        pbracket: ['{\\bigl #1 \\bigr}', 1],
        bvec:     ['{\\lgroup #1 \\rgroup}', 1],
        func:     ['{#1 \\left( #2 \\right)}', 2]
      }
    },

  MathMenu: {
      showFontMenu: true
    },

    menuSettings:{
      zoom: "None",
      zscale: "150%"
    },
    'HTML-CSS': {
      imageFont: null
    }
  });
  </script>

{% endif %}