I'm not sure if I'm understanding you correctly, but vanilla wasm ipc works by sharing linear memory, where it's up to the implementation to choose the data encoding (arrow/proto/whatever). In the case of wasm-bindgen's dom manipulation api, the implementation serialises individual commands and sends them over the boundary, with any string params for each command being deserialised individually, and this project improves on that by batching them all into one big string thus reducing the deserialisation overhead. However, the string encoding is specific to that use case - it's not a general wasm ipc mechanism.

VSCode IPC is kinda similar as it's designed to facilitate comms over an enforced process isolation barrier to protect the main thread from slow extensions etc. but it's actually IPC there (as in, there are multiple processes at the os level). The wasm/js stuff is handled within the same v8 context - it's not actually ipc.

(Happy to be corrected here, but this is my understanding)