Minimal, Reproducible Example

index.ts

import express from 'express';

const router = express.Router();

router.param('userId', (req, res, next, userId) => {
    next(userId.includes(':') ? 'route' : null);
});

router
    .get('/users/:userId::action', async (req, res) => {
        // Route 1.
        switch (req.params.action) {
            case 'ResetPassword':
                res.send('ResetPassword');
                break;
            case 'update':
                res.send('updated');
                break;
            default:
                res.send('invalid action');
                break;
        }
    })
    .get('/users/:userId', async (req, res) => {
        // Route 2.
        res.send(`Route 2`);
    });


const port = 3000;
const url = `http://localhost:${port}`;

const app = express();
app.use('/', router);
app.listen(port, () => {
    console.log(`Server started at ${url}`);
});