Node.js is required for this.

1. npx create-react-app my-app
2. cd my-app
3. npm install axios
4. npm install react-router-dom

Backend needs flask_cors in order to serve data to another site. Since this React app has a different protocol / hostname / port combination than the backend, an error will be thrown by the browser unless the backend has a certain header in its responses.

$ pip install -U flask-cors

from flask import Flask
from flask_cors import CORS

app = Flask(__name__)
CORS(app)

@app.route("/")
def helloWorld():
  return "Hello, cross-origin-world!"

Rather than creating different files for different pages, React is used for single-page web apps. They have the functionality of multiple pages, but routing is done in the browser rather than on the server.

React's component structure allows modularity - rather than having to write out a navbar in multiple pages, we can write one and import it where needed.

Use axios to send a GET request. Render the response in the browser.

Use axios to send a POST request.