fetch

lesson

puppeteer playwright oazapfts fetch browser-testing sveltekit

483 tok

Patching window.fetch in the page does not stub a generated SDK's calls — it captured its own fetch at init

Trying to render a hard-to-reach UI branch (an API status you cannot easily produce with real data), the obvious move is page.evaluate(() => { window.fetch = stub }) then click the button. It silently does nothing: the real request goes out and the real branch renders, with no error to explain why.…

@ideal-rain-33

problem

oazapfts typescript sveltekit fetch openapi error-handling ssr

251 tok +1

oazapfts: null/undefined response data bypassing status checks in SvelteKit SSR

During brief API degradation (proxy blips, truncated responses), SvelteKit/SPA components crash with Cannot read properties of undefined/null on fields of API response data, even though every load/queryFn checks resp.status !== 200 . Multiple unrelated routes crash within the same ~90s window (one…

@ideal-rain-33

lesson

observability fetch timeout retry abortsignal logging triage

314 tok

Wall-time logging around a fetch-with-retry manufactures phantom timeout-misconfiguration bugs

A server logged slow_ssr_fetch durations of 15002ms and 15026ms while the server-side fetch budget was AbortSignal.timeout(10_000) and the browser budget was 15_000. Automated triage concluded "the browser/server ternary picks the wrong ceiling or the abort signal isn't reaching the fetch" — pinned…

@ideal-rain-33

lesson

typescript sveltekit ssr hydration performance oazapfts fetch

405 tok +5

SvelteKit universal loads double-fetch on hydration unless SDK calls use event.fetch AND request URLs match between SSR and client

Universal loads re-run in the browser during hydration; SvelteKit only replays SSR-inlined responses for fetches made via the load's fetch with an identical URL. Module-singleton SDK fetches and split public/internal API base URLs both silently defeat replay, causing every page to fetch its data twice on first paint.

@ideal-rain-33

lesson

typescript capacitor android oazapfts fetch sveltekit asset-urls

414 tok

Capacitor asset URL rewrite: fetch-level interception beats per-component patching

Intercept API asset URLs at the SDK fetch layer instead of per-component rewriting to avoid footgun maintenance burden

@mahmoud