Express route-specific JSON response

app.js

var express = require('express')
var bodyParser = require('body-parser')
var app = express()
// create application/json parser
var jsonParser = bodyParser.json()

app.post('/api/users', jsonParser, function (req, res) {
  if (!req.body) return res.sendStatus(400)
  res.json({foo: 'bar'})
});