Testing cheerio for MathJax-node

cheerio_wrapper.js

#! /usr/bin/env node

var mjAPI = require("MathJax-node/lib/mj-single");
var typeset = mjAPI.typeset;
var fs = require('fs');
var path = require('path');
var async = require('async');
var cheerio = require('cheerio');


var argv = require("yargs")
    .strict()
    .usage("Usage: jats -i input.html -o output.html", {
        i: {
            describe: 'specify input file',
            alias: ('i', 'input')
        },
        o: {
            describe: 'specify output file',
            alias: ('o', 'output')
        }
    })
    .demand(['i', 'o'])
    .argv;


var inputFile = fs.readFileSync(path.join(__dirname, argv.i));

var $ = cheerio.load(inputFile);

mjAPI.config({
    MathJax: {
        menuSettings: {
            semantics: true,
        },
        "displayAlign": "left"
    }
});
mjAPI.start();

function processMath(mathNode, callback) {
    var thisMathNode = mathNode;
    var mmlString = $.html(mathNode);
    console.log(mmlString);
    typeset({
        format: "MathML",
        math: mmlString,
        svg: true,
    }, function(data) {
        if (!data.errors) {
            if (data.svg) {
                var svgNode = data.svg;
                $(thisMathNode).parent().append(svgNode);
            }
        }
        callback(data.errors);
    });
}

var mathNodes = $('mml\\:math, math').get();

async.each(mathNodes, processMath, function(err) {
    if (err) {
        throw err;
    }
    fs.writeFile(argv.o, $.html(), function(err) {
        if (err) {
            throw err;
        }
    });
    console.log("It\'s saved!");
});