res.app holds a reference to the Express application instance tied to the current
response — the same instance you'd get from req.app.
Syntax
res.app
Example
const express = require("express");
const app = express();
const PORT = 4800;
app.set("storeName", "PixelMart");
app.get("/about", (req, res) => {
console.log(res.app.get("storeName"));
res.send("PixelMart - About Page");
});
app.listen(PORT, () => console.log(`Listening on ${PORT}`));
Use cases
- Reading application-level settings from a response handler.
- Confirming a response object belongs to a particular app instance.
- Accessing shared app configuration inside custom response logic.