Send the idToken after authentication to server to generate customToken

sendIdToken.js

// Web: React

import { auth } from "./config/firebase";

auth.onAuthStateChanged((user) => {
	if (user) {
	  user.getIdToken(true).then((idToken) => {
	    // This is where to call the API
	
	    const requestOptions = {
	      method: "POST",
	      headers: { "Content-Type": "application/json" },
	      body: JSON.stringify({ idToken }),
	    };
	
	    fetch(
	      `https://native-redirect-firebase-admin.herokuapp.com/verify-token`,
	      requestOptions
	    )
	      .then((response) => response.json())
	      .then((data) => {
	        // Do stuff
	      })
	      .catch((error) => console.error(error));
	  });
	}
});