Warning
This package is not meant to be used directly, it's a shared dependency of sanity/presentation and @sanity/visual-editing. Using it in production is at your own risk.
The sanity/presentation tool requires a way to communicate with the application that lives within its preview iframe. The application is required to load up at least @sanity/visual-editing, but can also load up @sanity/core-loader, @sanity/next-loader, @sanity/svelte-loader, and @sanity/react-loader.
It uses @sanity/comlink to communicate over the iframe, and any popup preview windows, over the window.postMessage protocol.
The typings for those messages are defined in this package, as well as utils for maintaining compatibility with how older versions of sanity/presentation and @sanity/visual-editing used to format its message payloads, and helpers for handling payloads..