async-operations

Async Operations Skill

Iron Laws

ALWAYS use async/await over .then() chains — async/await produces linear, readable code; .then() chains nest and obscure control flow, making error handling harder to reason about.
ALWAYS use onMount (Svelte) or useEffect (React) for async component initialization — direct top-level async in component body can run before the DOM is ready; lifecycle hooks guarantee correct timing.
NEVER use forEach with async callbacks — array.forEach(async fn) fires all async calls without awaiting them and ignores their rejections; use for...of for sequential or Promise.all(array.map(async fn)) for parallel.
ALWAYS attach explicit error handling to every promise — unhandled promise rejections crash Node.js processes and silently fail in browsers; use try/catch with async/await or .catch() with .then() chains.
NEVER mix async/await and .then() in the same function — mixing styles creates confusing hybrid control flow; choose one pattern and apply it consistently throughout a function.

Anti-Patterns

Anti-Pattern Why It Fails Correct Approach

array.forEach(async fn)

Async callbacks are fire-and-forget; rejections are unhandled Use for...of (sequential) or Promise.all(arr.map(...)) (parallel)

Unhandled promise rejections Crashes Node.js; silently fails in browser Always wrap in try/catch or add .catch()

Mixing .then() and await

Confusing hybrid control flow; error scope unclear Use one style consistently per function

Top-level async in component body Runs before DOM is ready; race conditions Use lifecycle hooks (onMount , useEffect )

.then() chains 3+ levels deep Callback pyramid; hard to debug Convert to async/await for linear readability

Memory Protocol (MANDATORY)

Before starting:

cat .claude/context/memory/learnings.md

After completing: Record any new patterns or exceptions discovered.

ASSUME INTERRUPTION: Your context may reset. If it's not in memory, it didn't happen.

Source Transparency