Express backed that sends out customtoken for verified users

obtainCustomToken.js

// Backend: Node - Express

const express = require("express");
const admin = require("firebase-admin");

// Setup firebase admin [HERE]

// Route that handles GET request

app.post("/verify-token", (req, res) => {
  const { idToken } = req.body;

  admin
    .auth()
    .verifyIdToken(idToken)
    .then((decodedToken) => {
      admin
        .auth()
        .createCustomToken(decodedToken.uid)
        .then((customToken) => {
          return res.json({ customToken });
        })
        .catch((error) => {
          console.log("Error creating custom token: ", error);
        });
    })
    .catch((error) => {
      throw error;
      console.error(error);
    });

  return;
});

app.listen(5000, () => {
  console.log(`App is listening on port ${PORT}`);
});