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FileSystemWritableFileStream

Namespace: SpawnDev.SpawnJS.JSObjects
Inherits: WritableStream
Source: JSObjects/FileSystemWritableFileStream.cs
MDN Reference: FileSystemWritableFileStream on MDN

The FileSystemWritableFileStream interface of the File System API is a WritableStream object with additional convenience methods, which operates on a single file on disk. The interface is accessed through the FileSystemFileHandle.createWritable() method. https://developer.mozilla.org/en-US/docs/Web/API/FileSystemWritableFileStream

Constructors

Signature Description
FileSystemWritableFileStream(SpawnJSObjectReference _ref) Deserialization constructor

Methods

Method Return Type Description
Write(ArrayBuffer data) Task The write() method of the FileSystemWritableFileStream interface writes content into the file the method is called on, at the current file cursor offset.
Write(Blob data) Task The write() method of the FileSystemWritableFileStream interface writes content into the file the method is called on, at the current file cursor offset.
Write(TypedArray data) Task The write() method of the FileSystemWritableFileStream interface writes content into the file the method is called on, at the current file cursor offset.
Write(byte[] data) Task The write() method of the FileSystemWritableFileStream interface writes content into the file the method is called on, at the current file cursor offset.
Write(DataView data) Task The write() method of the FileSystemWritableFileStream interface writes content into the file the method is called on, at the current file cursor offset.
Write(string data) Task The write() method of the FileSystemWritableFileStream interface writes content into the file the method is called on, at the current file cursor offset.
Write(FileSystemWriteOptions data) Task The write() method of the FileSystemWritableFileStream interface writes content into the file the method is called on, at the current file cursor offset.
Truncate(ulong size) Task Resizes the file associated with the stream to be the specified size in bytes.
Seek(ulong position) Task Updates the current file cursor offset to the position (in bytes) specified.

Examples

SpawnDev.SpawnJS Mapping Note: The JavaScript examples below show the standard Web API usage. In SpawnDev.SpawnJS, the same API is available with C# conventions:

  • Properties and methods use PascalCase (e.g., readyState becomes ReadyState)
  • Events use ActionEvent with +=/-= (e.g., addEventListener("click", fn) becomes OnClick += handler)
  • Async methods return Task<T> instead of Promise<T>
  • Objects should be disposed with using statements
  • Access via JS.Get<FileSystemWritableFileStream>(...) or constructor new FileSystemWritableFileStream(...)
async function saveFile() {
  // create a new handle
  const newHandle = await window.showSaveFilePicker();

  // create a FileSystemWritableFileStream to write to
  const writableStream = await newHandle.createWritable();

  // write our file
  await writableStream.write("This is my file content");

  // close the file and write the contents to disk.
  await writableStream.close();
}
// just pass in the data (no options)
writableStream.write(data);

// writes the data to the stream from the determined position
writableStream.write({ type: "write", position, data });

// updates the current file cursor offset to the position specified
writableStream.write({ type: "seek", position });

// resizes the file to be size bytes long
writableStream.write({ type: "truncate", size });

See full example on MDN