We shipped FinalizationRegistry in Workers: why you should never use it

This post introduces the availability of the FinalizationRegistry API in Cloudflare Workers, detailing its purpose in managing external resources tied to garbage-collected JavaScript objects, particularly in the context of WebAssembly memory. It explains the differences in memory management between JavaScript (garbage collection) and WebAssembly (manual management), and demonstrates a pattern for using FinalizationRegistry to bridge this gap. However, it strongly advises against direct use due to the non-deterministic nature of garbage collection and highlights newer JavaScript features as more reliable solutions for preventing memory leaks and ensuring predictable resource cleanup.