Firebase function local dev react

There's a way to handle CORS requests in firebase cloud function, but for local development it makes mrore sense to setup your Create React App to be able to handle the functions locally as follows.

firebase.functions().useFunctionsEmulator('http://localhost:4001')

From How to test functions.https.onCall firebase cloud functions locally?

in context

import firebase from "firebase/app";
import "firebase/firestore";
import "firebase/auth";
import "firebase/storage";
import "firebase/functions";

const firebaseConfig = {
  apiKey: process.env.REACT_APP_API_KEY,
  authDomain: process.env.REACT_APP_AUTH_DOMAIN,
  databaseURL: process.env.REACT_APP_DATABASE_URL,
  projectId: process.env.REACT_APP_PROJECT_ID,
  storageBucket: process.env.REACT_APP_STORAGE_BUCKET,
  messagingSenderId: process.env.REACT_APP_MESSAGING_SENDER_ID,
  appId: process.env.REACT_APP_APP_ID,
  measurementId: process.env.REACT_APP_MEASUREMENT_ID
};

// Initialize Firebase
firebase.initializeApp(firebaseConfig);

export const db = firebase.firestore();
export const functions = firebase.functions();
// https://stackoverflow.com/questions/50884534/how-to-test-functions-https-oncall-firebase-cloud-functions-locally
firebase.functions().useFunctionsEmulator('http://localhost:4001') 
export default firebase;

from firebase API reference