| 1 | What is CORS and why does the browser block certain cross-origin requests? JavaScript › Networking: Fetch, XHR, WebSockets & CORS | JavaScript | Networking: Fetch, XHR, WebSockets & CORS | Intermediate |
| 2 | What is a CORS preflight request, and which requests trigger one? JavaScript › Networking: Fetch, XHR, WebSockets & CORS | JavaScript | Networking: Fetch, XHR, WebSockets & CORS | Advanced |
| 3 | How do Server-Sent Events (SSE) differ from WebSockets, and when would you choose them? JavaScript › Networking: Fetch, XHR, WebSockets & CORS | JavaScript | Networking: Fetch, XHR, WebSockets & CORS | Advanced |
| 4 | How do you make a basic GET request with fetch()? JavaScript › Networking: Fetch, XHR, WebSockets & CORS | JavaScript | Networking: Fetch, XHR, WebSockets & CORS | Beginner |
| 5 | How do you send a POST request with a JSON body using fetch()? JavaScript › Networking: Fetch, XHR, WebSockets & CORS | JavaScript | Networking: Fetch, XHR, WebSockets & CORS | Beginner |
| 6 | Why does fetch() NOT reject its Promise for HTTP error responses like 404 or 500? JavaScript › Networking: Fetch, XHR, WebSockets & CORS | JavaScript | Networking: Fetch, XHR, WebSockets & CORS | Intermediate |
| 7 | How do you cancel an in-flight fetch() request? JavaScript › Networking: Fetch, XHR, WebSockets & CORS | JavaScript | Networking: Fetch, XHR, WebSockets & CORS | Intermediate |
| 8 | What is XMLHttpRequest and why would you still use it over fetch() today? JavaScript › Networking: Fetch, XHR, WebSockets & CORS | JavaScript | Networking: Fetch, XHR, WebSockets & CORS | Advanced |
| 9 | How does a WebSocket connection differ fundamentally from repeated fetch() requests? JavaScript › Networking: Fetch, XHR, WebSockets & CORS | JavaScript | Networking: Fetch, XHR, WebSockets & CORS | Advanced |
| 10 | How would you implement request retries with exponential backoff and a total timeout using fetch()? JavaScript › Networking: Fetch, XHR, WebSockets & CORS | JavaScript | Networking: Fetch, XHR, WebSockets & CORS | Advanced |