mathjax-node

mathjax-node

This repository contains a library that provides an API to call MathJax from Node.js programs. The API converts individual math expressions (in any of MathJax's input formats) into HTML (with CSS), SVG, or MathML code.

Use

npm install mathjax-node

to install mathjax-node and its dependencies.

Note: The current version of mathjax-node requires Node.js v6 or later, and uses jsdom version 11.

Getting started

mathjax-node provides a library, ./lib/main.js. Below is a very minimal example for using it - the tests and the examples mentioned above provide more advanced examples.

// a simple TeX-input example
var mjAPI = require("mathjax-node");
mjAPI.config({
  MathJax: {
    // traditional MathJax configuration
  }
});
mjAPI.start();

var yourMath = 'E = mc^2';

mjAPI.typeset({
  math: yourMath,
  format: "TeX", // or "inline-TeX", "MathML"
  mml:true,      // or svg:true, or html:true
}, function (data) {
  if (!data.errors) {console.log(data.mml)}
  // will produce:
  // <math xmlns="http://www.w3.org/1998/Math/MathML" display="block">
  //   <mi>E</mi>
  //   <mo>=</mo>
  //   <mi>m</mi>
  //   <msup>
  //     <mi>c</mi>
  //     <mn>2</mn>
  //   </msup>
  // </math>
});

Documentation

mathjax-node exports three methods, config, start, typeset.

config(options)

The config method is used to set global configuration options. Its default options are

{
  displayMessages: false,    // determines whether Message.Set() calls are logged
  displayErrors:   true,     // determines whether error messages are shown on the console
  undefinedCharError: false, // determines whether "unknown characters" (i.e., no glyph in the configured fonts) are saved in the error array
  extensions: '',            // a convenience option to add MathJax extensions
  fontURL: 'https://cdnjs.cloudflare.com/ajax/libs/mathjax/2.7.2/fonts/HTML-CSS', // for webfont urls in the CSS for HTML output
  paths: {},                  // configures custom path variables (e.g., for third party extensions, cf. test/config-third-party-extensions.js)
  MathJax: { }               // standard MathJax configuration options, see https://docs.mathjax.org for more detail.
}

Note. Changes to these options require a restart of the API using the start() method (see below).

start()

The start method start (and restarts) mathjax-node. This allows reconfiguration.

Note. This is done automatically when typeset is first called (see below).

typeset(options[, callback])

The typeset method is the main method of mathjax-node. It expects a configuration object options and optionally a callback.

If no callback is passed, it will return a Promise.

Once called, typeset can be called repeatedly and will optionally store information across calls (see state below).

The following are the default input options.

{
  ex: 6,                          // ex-size in pixels
  width: 100,                     // width of container (in ex) for linebreaking and tags
  useFontCache: true,             // use <defs> and <use> in svg output?
  useGlobalCache: false,          // use common <defs> for all equations?
  linebreaks: false,              // automatic linebreaking
  equationNumbers: "none",        // automatic equation numbering ("none", "AMS" or "all")
  cjkCharWidth: 13,               // width of CJK character

  math: "",                       // the math string to typeset
  format: "TeX",                  // the input format (TeX, inline-TeX, AsciiMath, or MathML)
  xmlns: "mml",                   // the namespace to use for MathML

  html: false,                    // generate HTML output
  htmlNode: false,                // generate HTML output as jsdom node
  css: false,                     // generate CSS for HTML output
  mml: false,                     // generate MathML output
  mmlNode: false,                 // generate MathML output as jsdom node
  svg: false,                     // generate SVG output
  svgNode: false,                 // generate SVG output as jsdom node

  speakText: true,                // add textual alternative (for TeX/asciimath the input string, for MathML a dummy string)

  state: {},                      // an object to store information from multiple calls (e.g., <defs> if useGlobalCache, counter for equation numbering if equationNumbers ar )
  timeout: 10 * 1000,             // 10 second timeout before restarting MathJax
}

Promise.resolve(result,options) / Promise.reject(errors) / callback(result, options)

mathjax-node returns two objects to Promise.resolve or callback: a result object and the original input options.

The result object will contain (at most) the following structure:

{
  errors:                     // an array of MathJax error messages if any errors occurred
  mml:                        // a string of MathML markup if requested
  mmlNode:                    // a jsdom node of MathML markup if requested
  html:                       // a string of HTML markup if requested
  htmlNode:                   // a jsdom node of HTML markup if requested
  css:                        // a string of CSS if HTML was requested
  svg:                        // a string of SVG markup if requested
  svgNode:                    // a jsdom node of SVG markup if requested
  style:                      // a string of CSS inline style if SVG requested
  height:                     // a string containing the height of the SVG output if SVG was requested
  width:                      // a string containing the width of the SVG output if SVG was requested
  speakText:                  // a string of speech text if requested

  state: {                    // the state object (if useGlobalCache or equationNumbers is set)
           glyphs:            // a collection of glyph data
           defs :             // a string containing SVG def elements
           AMS: {
                startNumber:  // the current starting equation number
                labels:       // the set of labels
                IDs:          // IDs used in previous equations
             }
         }
}

If the errors array is non-empty, the Promise will reject, and be passed the errors array.

The options contains the configuration object passed to typeset; this can be useful for passing other data along or for identifying which typeset() call is associated with this (callback) call (in case you use the same callback function for more than one typeset()).

Change History

Breaking Changes in v2.0:

mathjax-node v2.0 makes breaking changes as follows:

• [CHANGED] mathjax-node now requires version 6 of Node.js (the minimum used to be Node.js version 4).
• [CHANGED] mathjax-node now uses version 10 of jsdom. Since the jsdom API changed from 9 to 10, that means if you used jsdom in your code that calls mathjax-node, you may need to update how you call jsdom.

Breaking Changes in v1.0:

mathjax-node v1.0 makes breaking changes to the following features from the pre-releases.

• [CHANGED] lib/mj-single.js has been renamed to lib/main.js (and set as main in package.json, i.e., require('mathjax-node') will load it.
• [REMOVED] lib/mj-page.js (API for processing HTML-fragments) and related CLI tools
• [REMOVED] speech-rule-engine integration
• [REMOVED] PNG generation
• [REMOVED] CLI tools in bin/

These features can easily be recreated in separate modules for greater flexibility. For examples, see

• mathjax-node-cli
• mathjax-node-page
• mathjax-node-sre
• mathjax-node-svg2png

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Be sure to also check out other projects on NPM that depend on mathjax-node.