Express req.ip returning object

Question

I have an express app:

const express = require('express');
const app = express();
const cors = require('cors');
app.use(cors({ optionsSuccessStatus: 200 }));
app.get('/api/whoami', (req, res) => {
    const ipaddress = req.ip;
    res.status(200).json({ ipaddress });
});
    
app.listen(process.env.PORT || 3000);    
module.exports = app;

and a test file:

const chai = require('chai');

const chaiHttp = require('chai-http');
const chaiMatch = require('chai-match');
const { describe, it } = require('mocha');
const server = require('../../server');

const should = chai.should();
const { expect } = chai;
chai.use(chaiHttp);
chai.use(chaiMatch);

describe('/GET /api/whoami', () => {
  it('should return the IP address', (done) => {
    chai.request(server)
      .get('/api/whoami')
      .end((err, res) => {
        res.should.have.status(200);
        res.body.should.be.a('object');
        res.body.should.have.property('ipaddress');
        expect(res.body.ipaddress).should.match(/* very long regex */);
        done();
      });
  });
});

for some reason, I keep geting Uncaught AssertionError: expected Assertion{ __flags: { …(4) } } to match [my very long regex], i didn't find anyone with the same error. How can I get my true ip with express? Or what is the right way to test it?

user_1871033 · Answer

The syntax is expect(something).to.match and not expect(something).should.match. See docs. Or, if you want to use should, you don't need expect, since the syntax for that is something.should.match.

The fix is therefore to change your code either as follows:

expect(res.body.ipaddress).to.match(/* very long regex */);

...or as follows:

res.body.ipaddress.should.match(/* very long regex */);

In the style guide, you get a good comparison between how to use expect and how to use should.

By mixing those two things, you took expect(...) which returns object that contains things like to and used it as source of your should, so that should.match check operated on the object returned by expect(...) and not the IP address itself.

Express req.ip returning object

1 Answers