katex-server/server.js

#!/usr/bin/env node
const katex = require('katex');
const express = require('express');
const bodyParser = require('body-parser');

app = express();
app.use(bodyParser.json());
app.post('/render', (req, res) => {
    res.send(req.body.equations.map(eq =>
        katex.renderToString(eq.str, { throwOnError: false, displayMode: eq.display })));
});
console.log('Starting KaTeX server');
app.listen(8000);