JavaScript Development Expert

Problem

Modern JavaScript projects often fail on subtle runtime behavior: hard-to-track Promise chains, async/await mixed with callbacks, lost errors, inconsistent Node.js and browser behavior, or ES6+ migration that breaks compatibility and bundle size. This skill targets those concrete issues rather than general JS basics.

How it works

It starts from runtime target, constraints, and module boundaries, then chooses async patterns such as async/await, Promise, generators, and clear exports. It covers ES6+ destructuring, classes, modules, event loop and microtask queue, Node.js APIs, performance tuning, browser compatibility, and TypeScript migration. Its approach favors avoiding callback-style code, handling errors at proper boundaries, using functional patterns where useful, and considering bundle size or polyfill strategy for browser code. Expected output includes maintainable module structure, race-condition prevention, JSDoc comments, async test patterns, and profiling notes.

Boundaries

Use it for modern JavaScript and async programming, not for TypeScript architecture design, non-JS runtimes, or backend architecture decisions. If the task centers on type systems, databases, service governance, or framework selection, choose a more specific architecture skill.