Easy up and running Create React App with Express backend running on Heroku with auto-deploys

react-express-heroku-quickstart.md

React Express Heroku Quickstart

npm init -y

Backend

create folder server and file index.js inside, with contents:

const express = require("express");

const PORT = process.env.PORT || 3001;

const app = express();

app.get("/api", (req, res) => {
  res.json({ message: "Connected to Server" });
});

app.listen(PORT, () => {
  console.log(`Server listening on ${PORT}`);
});

npm i express

In package.json (in root):

...
"scripts": {
  "start": "node server/index.js"
},
...

npm start and view http://localhost:3001/api to test our /api endpoint

Frontend

(from root): npx create-react-app client

In client/package.json, add:

"proxy": "http://localhost:3001",

cd client npm start

Now you can visit http://localhost:3001 to view your frontend

In client/src/App.js, replace any existing code with:

// client/src/App.js

import React from "react";
import "./App.css";

function App() {
  const [data, setData] = React.useState(null);

  React.useEffect(() => {
    fetch("/api")
      .then((res) => res.json())
      .then((data) => setData(data.message));
  }, []);

  return (
    <div className="App">
      <header className="App-header">
        <p>{!data ? "Loading..." : data}</p>
      </header>
    </div>
  );
}

export default App;

to test your api endpoint front the frontend

Server

Remove the client .git:

cd client
rm -rf .git

In server/index.js, you can now replace the contents with:

const express = require("express");
const path = require("path");

const PORT = process.env.PORT || 3001;

const app = express();

// Have Node serve the files for our built React app
app.use(express.static(path.resolve(__dirname, "../client/build")));

// Handle GET requests to /api route
app.get("/api", (req, res) => {
  res.json({ message: "Connected to Server" });
});

// All other GET requests not handled before will return our React app
app.get("*", (req, res) => {
  res.sendFile(path.resolve(__dirname, "../client/build", "index.html"));
});

app.listen(PORT, () => {
  console.log(`Server listening on ${PORT}`);
});

and now in the root package.json:

// server/package.json

...
"scripts": {
    "start": "node server/index.js",
    "build": "cd client && npm install && npm run build"
  },
  ...

and also add your version of node to package.json (you can get version with node --version)

"engines": {
  "node": "your-node-version"
}

Add a root .gitignore file, with, at the minimum:

node_modules
.env
.DS_STORE

Create heroku account and install heroku cli:

sudo npm i -g heroku

Then heroku login

Create a repo on github (or elsewhere), and add its URL as a remote

git init
git add .
git commit -m "first commit"
git branch -M main
git remote add origin https://github.com/[YOUR_USERNAME]/[YOUR_REPO_NAME].git
git push -u origin main

Add Heroku Remote

Create an App on Heroku and then add it as a remote via the command line:

heroku git:remote -a insert-your-app-name-here
git commit -am "Deploy app to Heroku"

Now deploy to Heroku and your app will be live:

git push heroku main