Unable to make app.post working using nodeJs - node.js

Question

I am trying to connect my Angular2 to my nodeJs server. I have an authentication form which makes a post request. And I would like to use node to handle the post request.
But so far I am unable to make my post request working. The console.log doesn't display anything.
What I am missing?
This is my server.js which points to the folder dist in which i made the build of angular.
const express = require('express');
const path = require('path');
const http = require('http');
var walker = require('node-sync-walker');
const bodyParser = require('body-parser');
// Get our API routes
const api = require('./server/routes/api');
var app = express();
// Parsers for POST data
app.use(bodyParser.json());
app.use(bodyParser.urlencoded({ extended: false }));
// Point static path to dist
app.use(express.static(path.join(__dirname, 'dist')));
// Set our api routes
app.use('/api', api);
// Catch all other routes and return the index file
app.get('/', (req, res) => {
res.sendFile(path.join(__dirname, 'dist/index.html'));
});
walker.routeWalker(__dirname + '/server/routes', app);
/**
* Get port from environment and store in Express.
*/
const port = process.env.PORT || '3000';
app.set('port', port);
/**
* Create HTTP server.
*/
const server = http.createServer(app);
/**
* Listen on provided port, on all network interfaces.
*/
server.listen(port, () => console.log(`API running on localhost:${port}`));
This is my api.js
var users = [{username: "user", password: "password"}];
var router = require('express').Router();
module.exports = function(app) {
router.post('/api/authenticate',
function(req, res) {
console.log("print something");
let params = JSON.parse(req.body);
// find if any user matches login credentials
let filteredUsers = users.filter(user => {
return user.username === params.username && user.password === params.password;
});
if (filteredUsers.length) {
res.sendStatus(200);
} else {
console.log("print something else");
return res.sendStatus(400)
}
//return;
});
}

Answer 1

You are configuring the route as '/api/api/authenticate'
You should remove '/api' from routes in api.js

Answer 2

Finally, it worked! I removed the api in /api/authenticate as #catalacs suggested. Then I changed how I import the module router from api.js to server.js.
server.js
var users = [{username: "test", password: "test"}];
var router = require('express').Router();
router.post('/authenticate',
function(req, res) {
console.log("print something");
let params = JSON.parse(req.body);
// find if any user matches login credentials
let filteredUsers = users.filter(user => {
return user.username === params.username && user.password === params.password;
});
if (filteredUsers.length) {
res.sendStatus(200);
} else {
console.log("print something else");
return res.sendStatus(400)
}
//return;
});
module.exports = router;
And in my server.js, I commented out this line:
walker.routeWalker(__dirname + '/server/routes', router);