req.app Property

req.app gives a route handler or middleware access to the current Express application instance, so you can read settings stored with app.set().

Syntax

req.app

Example

const express = require("express");
const app = express();
const PORT = 4700;

app.set("storeName", "PixelMart");

app.get("/", (req, res) => {
    console.log(req.app.get("storeName"));
    res.send("Store name logged on the server");
});

app.listen(PORT, () => console.log(`Listening on ${PORT}`));

Visiting / logs PixelMart on the server console.

Use cases

Reading application-wide configuration from inside a route.
Sharing values set once at startup with every request handler.
Accessing Express app methods from deep inside middleware.