Code Complexity Async APIs + worker management = verbose Simple sync code with powerful concurrency primitives Performance Good for limited parallel tasks; costly to scale Excellent for high-volume, fine-grained concurrency Suitability for Compiler Feasible but harder to scale, debug, and optimize Ideal for parsing, analyzing, and transforming in parallel GC Behavior One V8 GC per thread (heavy) Unified, efficient GC tuned for concurrency