Document buffers

An action that formats a file has to change something. Changing the provider means every transform is a write; changing nothing means the transform is a lie. A document buffer is the third option.

import { openDocument, setDocumentContent, saveDocument, isDocumentDirty } from '@textui/documents';

const doc = await openDocument(app, uri);      // reads through the provider, once
setDocumentContent(app.store, uri, formatted); // every viewer of that URI updates
isDocumentDirty(app.store, uri);               // content !== what was read
await saveDocument(app, uri);                  // writes back, or throws if read-only

In a component:

const doc = useDocument(uri);
doc.content; doc.dirty; doc.readonly;
doc.set(next); doc.revert(); doc.reload(); await doc.save();

Buffers live at $/session/documents/<uri>, so they die with the process. The viewers shipped here read them, which is why running “Format” on a file from a read-only provider shows you the formatted document and changes nothing on disk.