# FileWrapperDocumentWriter A document writer that serializes a snapshot into a `FileWrapper`. ``` struct FileWrapperDocumentWriter ``` ## Overview The `makeFileWrapper` closure in [`init(_:makeFileWrapper:)`](/documentation/SwiftUI/FileWrapperDocumentWriter/init(_:makeFileWrapper:)) turns the document’s snapshot into a `FileWrapper` that SwiftUI writes to disk. It receives the current snapshot and, when available, the `FileWrapper` from the document’s last read or write. For documents written as a single file, ignore `previous` and return a freshly built wrapper: ``` extension TextDocument: WritableDocument { func writer( configuration: sending WriteConfiguration ) -> sending FileWrapperDocumentWriter { FileWrapperDocumentWriter(configuration) { snapshot, _ in FileWrapper(regularFileWithContents: Data(snapshot.utf8)) } } // ... } ``` ## Topics ### Creating a writer [`init(_:makeFileWrapper:)`](/documentation/SwiftUI/FileWrapperDocumentWriter/init(_:makeFileWrapper:)) Creates a writer that converts a snapshot into a `FileWrapper`. [`WriteConfiguration`](/documentation/SwiftUI/FileWrapperDocumentWriter/WriteConfiguration) ### Writing a document ## Relationships ### Conforms To [`DocumentWriter`](/documentation/SwiftUI/DocumentWriter) --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)