Promise Polyfills and Promise Related APIs Questions

Implement a basic Promise from scratch, understanding state management (pending, fulfilled, rejected), then/catch chaining, and microtask queue concepts. Implement Promise-related methods like Promise.all (wait for all), Promise.race (first to settle), Promise.allSettled (all complete regardless of result), and Promise.any (first to fulfill). Handle edge cases like empty arrays, synchronous vs asynchronous resolution, and error propagation. Discuss how Promises improve upon callbacks.