Get parameter from previous route handler in express js

Question

Say I have file1.js:

import Router from "express-promise-router";

export const router1 = Router();

router1.get("/", async (req, res) => {

      // I want to get here :id from router2 in file2

})

And file2.js (in the same directory for simplicity):

import Router from "express-promise-router";

import { router1 } from "./file1";

export const router2 = Router();

router2.use("/:id/path", router1);

I want to use /:id from file2.js in file1.js (see my comment in example code).

How can I do that? In other words, how can I percolate '/:something' parameter down the routers chain?

Note - this doesn't work:

router1.get("/", async (req, res) => {

      const { params: {id} } = req;

})

Answer 1

I found the answer. From express api:

So should add the option mergeParams set to true when declaring the router handler.

In general: const router = express.Router({mergeParams: true});.

For the question's example code in file1.js:

import Router from "express-promise-router";

export const router1 = Router({mergeParams: true});

router1.get("/", async (req, res) => {

      const { params: {id} } = req; // now this works

})