javascript-pro

Async/await patterns let you write asynchronous code that reads like synchronous logic. Use the async keyword on functions, await to pause on Promises, and try/catch for error handling. This approach simplifies Promise chains and improves readability in Node.js and browser applications.

Optional chaining (?.) safely accesses nested properties without null checks; nullish coalescing (??) provides default values for null or undefined. These ES2023+ features reduce boilerplate, prevent runtime errors, and improve code clarity in modern JavaScript applications.

Yes, top-level await lets you use await outside async functions in ES modules (ESM), enabling dynamic imports and initialization at module load time. This simplifies module setup in Node.js and modern frontend bundlers without requiring wrapper functions.

Wrap async/await code in try/catch blocks to catch Promise rejections. Combine this with proper error logging, JSDoc documentation, and Jest tests to verify error paths. Robust error handling prevents silent failures and improves debugging in production applications.

ESM (import/export) is the modern standard for JavaScript modules with static analysis and tree-shaking support; CommonJS (require) is Node.js's older pattern. ESM enables top-level await and dynamic imports, while CommonJS remains common in legacy Node.js applications. Both can coexist in modern projects.

Jest handles async/await natively—return Promises or use async test functions. Combine with mocking for Fetch API calls and file operations, then measure coverage with Jest's built-in tools. Aim for 85%+ coverage to catch edge cases in Promise chains and error handlers.