Quick MathJax-node wrapper for xhtml files containig MathML

mj-node-xhtml-with-mml.js

'use strict';
var mjAPI = require('mathjax-node/lib/mj-single');
var typeset = mjAPI.typeset;
var fs = require('fs');
var libxmljs = require('libxmljs');


var argv = require('yargs')
    .strict()
    .usage('Usage: jats -i input.html -o output.html -f HTML', {
        i: {
            describe: 'specify input file',
            alias: ('i', 'input')
        },
        o: {
            describe: 'specify output file',
            alias: ('o', 'output')
        },
        f: {
            default: 'HTML',
            describe: 'output format to generate -- HTML or SVG'
        },
    })
    .demand(['i'])
    .argv;

var inputFile = fs.readFileSync(argv.i);
var outputFile = argv.o
var xmlDocument = libxmljs.parseXmlString(inputFile);

mjAPI.config({
    MathJax: {
        menuSettings: {
            semantics: true,
        },
        'displayAlign': 'left',
        TeX: {
            TagSide: 'left',
            Macros: {
                bigsqcap: '\\mmlToken{mo}{\u2a05}',
                lefteqn: ['\\rlap{\\displaystyle{#1}}', 1]
                    // btran 8
            }
        }
    }
});
mjAPI.start();

var mathNodes = xmlDocument.find('//*[name() = "math"]'); // cf. http://stackoverflow.com/a/10990253
// For TeX or ascii input, this might be
// var texMathNodes = xmlDocument.find('.//*[name()="span"][@class="math"]');
// For TeX, you'd need some delimiter handling
// e.g., use class="math block" without delimiters or use delimiters and check innerHTML for them.

var state = {}; // shared state among typeset requests (SVG <defs> for global sprite are stored here);  cf useGlobalCache

for (var i = 0; i < mathNodes.length; i++) {
    let index = i;
    let element = mathNodes[index];
    mjAPI.typeset({
        math: element.toString(),
        format: 'MathML',
        svg: (argv.f === 'SVG'),
        useGlobalCache: true,
        state: state,
        html: (argv.f === 'HTML'),
        speakText: true
            // TODO: handle state
    }, function(data) {
        if (data.errors) {
            throw data.errors;
        }
        if (data.svg) {
            console.log("Hello" + index);
            var svgNode = libxmljs.parseXmlString(data.svg);
            element.replace(svgNode.root());
        }
        if (data.html) {
            var htmlNode = libxmljs.parseHtmlString(data.html);
            element.replace(htmlNode.root());
        }
        // wrap up at end of loop
        // (typesetting is async but guaranteed to be in series.)
        if ((index + 1) === mathNodes.length) {
            if (data.svg) {
                var body = xmlDocument.find('//*[name() = "body"]')[0];
                var globalSVG = libxmljs.parseXmlString("<svg style='display:none'>" + state.defs.outerHTML + "</svg>"); // the SVG sprite
                body.addChild(globalSVG.root());
            }
            fs.writeFile(outputFile, xmlDocument, function(err) {
                if (err) {
                    throw err;
                } else {
                    console.log("It\'s saved!");
                }
            });
        }
    });
}