This API enables developers to build powerful apps that interact with other (non-Web) apps on the user’s device via the device’s file system. After a user grants a web app access, this API allows the app to read or save changes directly to files and folders selected by the user. Beyond reading and writing files, this API provides the ability to open a directory and enumerate its contents, as well as store file and directory handles in IndexedDB to later regain access to the same content.
Today, if a website wants to create experiences involving local files (document editor, image compressor, IDE, etc.) they are at a disadvantage to native apps. A web site must ask the user to reopen a file every time they want to edit it. After opening, the site can only save changes by re-downloading the file to the Downloads folder. A native app, by comparison, can maintain a most recently used list, re-save and even auto save, and save files anywhere the user wants.
Docs: https://web.dev/file-system-access/ https://web.dev/browser-nativefs/
Samples: https://github.com/GoogleChromeLabs/text-editor https://googlechromelabs.github.io/text-editor/
Explainers: https://github.com/WICG/file-system-access/blob/master/EXPLAINER.md