Express rendering in/after post - node.js

Question

Web app routing novice here. I've got a relatively simple app working based on Node/Express.
The main index of the app is a list of user names, and IDs.
localhost:242
Every user ID is a link to a page with a form to enter additional metadata about that particular user.
localhost:242/user/1398
Everything is working correctly. When I enter some metadata about the user, and submit the form, a POST route is executed, and then I'm redirected back to the original page I was on. Instead of using a redirect, I'd like to be able to re-render that same page, so I can pass some confirmation messages indicating what was just changed.
Here's a simplified version of my code.
// Module imports
var express = require('express');
var validator = require('express-validator');
var router = express.Router();
router.get('/', function(req, res, next) {
db.dataTalk(queryUsers, null, config.connection, function(err, result) {
var listUsers = result;
res.render('index', {
// Index with list of users
title: 'Page Title',
listUsers: listUsers
});
});
});
// GET /user/:id
router.get('/user/:id', function(req, res, next) {
db.dataTalk(queryUserDeets, [req.params.id], config.connection, function(err, result) {
// Details for a single user
var userDetails = result;
res.render('user', {
title: req.params.id,
userDetails: userDetails
});
});
});
// POST /user-update
router.post('/user-update', function(req, res) {
// Here goes a lot of logic to validate the form contents, and update the appropriate databases
// Redirect back to the user page, which should display the updated metadata
res.redirect('/user/' + req.body.userInitID);
});
module.exports = router;

Answer 1

Extract a helper function you can call from both places. Here's one that sticks very close to your original code.
function renderUserPage (userId, res) {
db.dataTalk(queryUserDeets, [userId], config.connection, function(err, result) {
// Details for a single user
var userDetails = result;
res.render('user', {
title: userId,
userDetails: userDetails
});
});
});
// GET /user/:id
router.get('/user/:id', function (req, res) {
renderUserPage(req.params.id, res)
});
// POST /user-update
router.post('/user-update', function(req, res) {
// Here goes a lot of logic to validate the form contents, and update the appropriate databases
// Redirect back to the user page, which should display the updated metadata
renderUserPage(req.body.userInitID, res);
});
Aside: You are ignoring errors from database calls. If you don't at the very least log something for each and every error passed to an async callback, you are going to be blind to problems that would otherwise be straightforward to debug.