A deep dive into async resource leaks in JavaScript caused by Promise.all not cancelling orphaned tasks when one fails. Covers three real production failure patterns (abandoned fetches, zombie DB queries, bound ports), then explains how ES2026 primitives fix them: `await using` with Symbol.asyncDispose for guaranteed cleanup, and AbortSignal.any() for composed cancellation. Shows how to build a TaskScope abstraction combining both, integrates AsyncLocalStorage for ambient request context in Node.js 24, and briefly covers the Effection library as an alternative. Honestly acknowledges that JavaScript still lacks enforced structured concurrency unlike Go, Kotlin, or Swift.
Table of contents
The Three Failure Modes Worth KnowingWhat ES2026 Actually Gives YouBuilding a Task ScopeAsyncLocalStorage as Context CarrierWhen to Reach for EffectionThe Honest LimitationMaking It Stick in PracticeSort: