The Origin Private File System (OPFS, part of the File System Access API) is augmented with a new surface that brings very performant access to data. This new surface differs from existing ones by offering in-place and exclusive write access to a file’s content. This change, along with the ability to consistently read unflushed modifications and the availability of a synchronous variant on dedicated workers, significantly improves performance and unblocks new use cases.
Our goal is to give developers flexibility by providing generic, simple, and performant primitives upon which they can build higher-level storage components. The new surface is particularly well suited for Wasm-based libraries and applications that want to use custom storage algorithms to fine-tune execution speed and memory usage.
Explainers: https://github.com/WICG/file-system-access/blob/main/AccessHandle.md