const express = require('express');
const request = require('request');

const app = express();

app.use((req, res, next) => {
  res.header('Access-Control-Allow-Origin', '*');
  next();
});

app.get('/chainz/api/:coinname/:address', (req, res) => {
console.log(req.params.coinname);
console.log(req.params.address);
  request(
    { url: 'https://chainz.cryptoid.info/${req.params.coinname}/api.dws?q=getbalance&a=${req.params.address}' },
    (error, response, body) => {
      if (error || response.statusCode !== 200) {
        return res.status(500).json({ type: 'error', message: err.message });
      }

      res.send(body);
      }
    )
  });

  const PORT = process.env.PORT || 5555;
  app.listen(PORT, () => console.log(`listening on ${PORT}`));




Error

/api-pass/index.js:18
        return res.status(500).json({ type: 'error', message: err.message });
                                                              ^

ReferenceError: err is not defined