"Cannot find module /es5/input/tex.js" error in Windows Node

[curbengh]

Issue Summary

I'm trying to integrate mathjax (tex => svg) into this node app (hexojs/hexo-math#130). Unit test ran fine in GitHub Actions' Ubuntu and OSX environments but failed in Windows with MathJax(input/tex): Cannot find module '/es5/input/tex.js' error (log).

Affects Node 10, 12 & 14. Same issue in Travis.

Steps to Reproduce:

lib/mathjax.js

const { init } = require('mathjax');

module.exports = hexo => {
  return async function mathjaxFn(args, content) {
    if (this.mathjax === false) return content;

    const { options: globalCfg } = hexo.config.math.mathjax;
    const { mathjax: fmCfg } = this;
    const [jsonCfg] = args;
    const argsCfg = jsonCfg ? JSON.parse(jsonCfg) : false;
    let options = Object.assign({}, globalCfg);
    if (fmCfg) options = Object.assign({}, options, fmCfg);
    if (argsCfg) options = Object.assign({}, options, argsCfg);
    const { conversion, svg, tex } = options;

    const MathJax = await init({
      loader: {
        load: ['input/tex', 'output/svg']
      },
      tex,
      svg
    });

    const { startup, tex2svgPromise } = MathJax;
    const svgOut = await tex2svgPromise(content, conversion);

    return startup.adaptor.outerHTML(svgOut);
  };
};

Unit test test/index.js

    describe('mathjax', () => {
      const m = require('../lib/mathjax')(hexo).bind({});
      const content = '\\frac{1}{x^2-1}';
      const displayFalse = '<mjx-container class="MathJax" jax="SVG">';
      const displayTrue = '<mjx-container class="MathJax" jax="SVG" display="true">';

      it('default', async () => {
        const output = await m(args, content);

        output.startsWith(displayFalse).should.eql(true);
      });
    });

Technical details:

• MathJax Version: 3.0.5
• OS: Windows Server 2019
• Nodejs: v10.21.0, v12.18.2, v14.5.0

Supporting information:

hexojs/hexo-math#130

Configuration ./index.js

  mathjax: {
    options: {
      // https://docs.mathjax.org/en/latest/web/typeset.html#conversion-options
      conversion: {
        display: false
      },
      // https://docs.mathjax.org/en/latest/options/input/tex.html
      tex: {},
      // https://docs.mathjax.org/en/latest/options/output/svg.html
      svg: {}
    }
  }

[dpvc]

Thanks for the report. It looks like MathJax is having trouble locating its package directory in Windows. I'm able to reproduce the problem, and will look into it further. In the meantime, you can add

        paths: {mathjax: 'mathjax/es5'},

to the loader configuration passed to MathJax's init() function, and that should allow it to work on Windows (and everywhere else). So you would use

    const MathJax = await init({
      loader: {
        paths: {mathjax: 'mathjax/es5'},
        load: ['input/tex', 'output/svg']
      },
      tex,
      svg
    });

See if that works for you.

[curbengh]

Thanks, WFM in Actions & Travis.

[dpvc]

It turns out that the copy of node's path module that webpack uses doesn't understand Windows paths that include backslashes, and that was the source of the problem, here. I've made a PR (see link above) to resolve the issue.

[dpvc]

Fixed in v3.1 released today.