It turned out that File System Access API is not deprecated, it's just not standardised (May 2021); the deprecated one is the function window.requestFileSystem
; the same function on Chromium-based browsers is window.webkitRequestFileSystem
.
File System API
is for creating a virtual drive (temporary or persistent) for each website when using browser-based db (IndexedDB) is not necessary especially for the purpose of storing files.
https://developer.mozilla.org/en-US/docs/Web/API/FileSystem
File System Access API
is different, it is for accessing the real file system of the OS. This API is now standardised and available on Chromium-based browsers (May 2021). Firefox has not yet adapted this API.
https://developer.mozilla.org/en-US/docs/Web/API/File_System_Access_API
Status of these APIs: https://developer.mozilla.org/en-US/docs/Web/API