req.accepts() Function

req.accepts() checks a client's Accept header against the content types you offer, and returns the best match, or false if nothing matches.

Syntax

req.accepts(types)

Example

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

app.get("/report", (req, res) => {
    const type = req.accepts(["json", "html"]);

    if (type === "json") {
        return res.json({ report: "monthly-sales" });
    }
    if (type === "html") {
        return res.send("<h1>Monthly Sales Report</h1>");
    }
    res.status(406).send("Not Acceptable");
});

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

A request with Accept: application/json gets a JSON response; Accept: text/html gets HTML.

Use cases

• Content negotiation between JSON, HTML, XML, and other formats.
• Serving the same endpoint differently depending on the client.
• Returning 406 Not Acceptable for unsupported formats.