fetch GET request fetch POST JSON Request headers Query parameters URLSearchParams Request body Response status Response headers JSON response Text response

HTTP methods credentials option mode option cache option redirect option referrerPolicy option integrity option keepalive option priority hint custom Request object

async await fetch Promise chaining Parallel requests Promise.allSettled Sequential requests Retry with backoff Timeout with AbortController Cancel request Race requests Request deduplication

FormData submission URL encoded form File upload Multiple file upload Upload progress limitation JSON form submission CSRF token header Disable submit while pending Optimistic UI Validation response handling

Network error HTTP error handling 404 handling 401 handling 429 handling 500 handling Malformed JSON AbortError Offline detection Fallback UI

Same-origin policy CORS simple request CORS preflight Access-Control-Allow-Origin Credentials with CORS CSRF considerations Content-Type constraints Avoid exposing secrets CSP connect-src HTTPS requests

ReadableStream response Streaming text NDJSON stream Server-sent events comparison Blob response ArrayBuffer response Clone response Response.bodyUsed Service worker interception Beacon comparison

API client wrapper Centralized error handling Request interceptor pattern Response normalization Mock fetch Dependency injection Cache API integration ETag conditional request Pagination requests Infinite scrolling