The optimization is usually called shapes outside of JS. The idea is that shapes (we represent objects like C like structs and not hash maps) are used for rela

The optimization is usually called shapes outside of JS. The idea is that shapes (we represent objects like C like structs and not hash maps) are used for relatively non-dynamic objects and then we keep the shape metadata on functions themselves (inline caches) which means property access becomes just a byte offset. See https://v8.dev/blog/fast-properties https://v8.dev/blog/fast-properties