Quick & Dirty Example of how to setup a proxy to locally test rest request from SapUI5 avoiding CORS
Open 3 consoles.
On console #1: cd into "frontend" run "npm run start"
On console #2: cd into "backend" run "node index.js"
On console #3: cd into "proxy" run "node proxy.js"
Open browser with "http://localhost:8080/index.html" and you should see the start page. Click the "Say Hello" button to view the successful rest response.