Firebase exchange a refresh token for an ID token

get-id-token.ts

import axios from "axios";
import { Auth } from "firebase-admin/auth";

export const getIdToken = async (auth: Auth, uid: string) => {
  const customToken = await auth.createCustomToken(uid);
  const res = await axios.post(
    `http://localhost:[PORT]/www.googleapis.com/identitytoolkit/v3/relyingparty/verifyCustomToken?key=[KEY]`,
    {
      token: customToken,
      returnSecureToken: true,
    }
  );
  return res.data.idToken;
};