Promise Polyfills
Promise.all, race, allSettled, promisify
Recreate Promise static methods and async utilities to demonstrate mastery of JavaScript concurrency. Implementing Promise.all, Promise.race, Promise.allSettled, and promisify requires understanding Promise resolution, error propagation, and the microtask queue. These are high-signal interview questions that separate junior from senior engineers.
Practice 11 interactive coding problems with step-by-step execution visualization.
Promise.all, race, allSettled, promisify