Axios POST request scenarios with CORS guide on localhost while working in production
I'm reviewing some code and I'm working on a project and hit a roadblock. I'm working with a CORS policy scenario when making an Axios POST request from my React application. The application runs perfectly in production, but when I try to execute the same request on localhost, it throws the following behavior: `Access to XMLHttpRequest at 'http://api.example.com/data' from origin 'http://localhost:3000' has been blocked by CORS policy`. I've configured my server to allow CORS, using the `cors` middleware in Express like so: ```javascript const express = require('express'); const cors = require('cors'); const app = express(); app.use(cors({ origin: 'http://localhost:3000' })); ``` When I check the network tab, I can see the request is sent, but the preflight OPTIONS request fails. I tried sending a simple request to the same endpoint using Postman, and it works without any issues. In my React component, I have the following Axios POST request: ```javascript import axios from 'axios'; const submitData = async (formData) => { try { const response = await axios.post('http://api.example.com/data', formData); console.log(response.data); } catch (behavior) { console.behavior('behavior during POST request:', behavior); } }; ``` I've double-checked that both my frontend and backend are running on the expected ports. Also, I've verified that no browser extensions are interfering with CORS. The server logs show that requests are reaching the backend, but the CORS headers are not being returned correctly for the OPTIONS request. Has anyone experienced a similar scenario? What else can I check or modify to resolve this CORS-related question on localhost? Cheers for any assistance! I'm on Ubuntu 20.04 using the latest version of Javascript.