🛑 Cancel In-Flight Requests
User navigates away mid-request. Old request completes, updates wrong page. Prevent this.
const controller = new AbortController();
fetch('/api/data', { signal: controller.signal })
.then(res => res.json())
.catch(err => {
if (err.name === 'AbortError') {
console.log('Request cancelled');
}
});
// User navigates away
controller.abort(); // Cancels request
React Hook: Use in useEffect cleanup. Cancel on unmount.
Search Box: Cancel previous search when user types. Only latest search completes.
Performance: Save bandwidth, prevent race conditions.