**Learning:** `useMemo` can significantly boost the performance of long list or grid components (like `PhotoGrid` component) that otherwise gets re-rendered on simple interactions like navigating the image lightbox. Running standard formatting `pnpm format` applies huge changes across entire directories, so it's generally best to format and clean up ONLY modified files to avoid huge diff pollution in code review.
**Action:** Be extremely cautious of running format/lint commands at the root codebase; specify only modified directories or files, or avoid formatting if it cascades globally. Focus on targeted memoization where state changes dictate expensive array mapping operations.
## 2024-05-28 - [Deduplicate concurrent API requests via Promise caching]
**Learning:** When using `Promise.all` to fetch dependent data in parallel (e.g., getting multiple subpages and standalone albums that internally call a shared `getAlbums` function), the internal cache might not be populated in time. This leads to redundant concurrent network requests to the upstream server.
**Action:** Implement Promise deduplication (request coalescing) by caching the pending Promise itself (e.g., in a `this.pendingPromise` class field) rather than just the final result. Return the pending Promise to subsequent callers until it resolves, ensuring only one network request is made.
**Learning:** `Buffer` inherits from `Uint8Array` in Node.js. Passing a `Buffer` into `new Uint8Array(...)` creates a completely new `ArrayBuffer` and copies all elements, which is an O(N) memory allocation and copy.
**Action:** When decoding base64 strings or similar byte streams in Node.js where a `Uint8Array` is expected, return `Buffer.from(data, 'base64')` directly instead of wrapping it.
