Can't receive a response message when using proxy-middleware between react ui and express backend - express

Question

I see that the request sent from the ui created using React is forwarded to the backend, but I can't get the response from the ui. There may be details that I missed as I am very new to these issues, thanks in advance :)
//react Login.js
function Login() {
const fetch = actions.fetchUser();
async function handleSubmit() {
try {
fetch();
} catch (err) {
console.error('err', err);
}
}
export default Login;
//index.js
import axios from 'axios';
export const fetchUser = () => async () => {
await axios.get('/api/login');
};
//setupProxy.js
const { createProxyMiddleware } = require('http-proxy-middleware');
module.exports = function (app) {
app.use(
['/api'],
createProxyMiddleware({
target: 'http://localhost:5000',
}),
);
};
//express app.js
const express = require('express');
const bodyParser = require('body-parser');
const cors = require('cors');
const app = express();
const port = 5000;
app.use(cors());
app.use(bodyParser.json());
require('./routes/login')(app);
app.listen(port, () => {
console.log(`Example app listening on port ${port}`)
})
// espress login.js
module.exports = app => {
app.get('/api/login', (req, res) => {
console.error('express login');
res.send('login');
});

Answer 1

First of all, do not mix cjs and mjs import/exports.
second of all, you export your middleware but never register/use it. At least your code does not show that part.
Here is very minimal example how you can proxy your react UI via express.
const express = require('express');
const proxy = require('express-http-proxy');
const app = express();
app.get('/api', (req, res) => {
res.send({my: 'data'});
});
// register other routes here
app.use(proxy('http://127.0.0.1:3000'));
app.listen(5000, '0.0.0.0', () => {
console.log('Server is running at http://127.0.0.1:5000');
});
React app content will be available on http://127.0.0.1:5000 with your routes.
And http://127.0.0.1:5000/api will be your express route.
Note: I assume your react app runs on the port 3000