Lesson 5.3 of the JavaScript tutorial — async/await in depth: what async/await actually do, error handling with try/catch, the sequential-vs-parallel trap, Promise.all/allSettled/race/any, top-level await, and the patterns experienced developers reach for.
JavaScript async/await Explained: How It Really Works (and How to Use It Well) Read More »
try/catch only catches synchronous throws inside the try block. Async callbacks, uncaught promises, and event handlers all need different patterns. Custom Error subclasses, the Result type, Error.cause, Promise.allSettled, and the global safety nets you must install.
JavaScript Error Handling Patterns: try/catch, Result Types, and async/await Read More »
Build a Promise from scratch in 60 lines. State machine (pending → fulfilled / rejected), why callbacks run as microtasks, how chaining works (then returns a new Promise that adopts the inner result’s state), catch/finally as sugar, and how async/await desugars to .then.
The event loop coordinates JavaScript’s single call stack with the microtask and macrotask queues. Why Promise.then always runs before setTimeout(0), what counts as a microtask vs macrotask, how rendering fits in, microtask starvation, and the await-in-a-loop trap.
The JavaScript Event Loop, Microtasks vs Macrotasks (with Timing Examples) Read More »