BunFile.writer

interface FileSink

• end(

  error?: Error

  ): number | Promise<number>;

  Close the file descriptor. This also flushes the internal buffer.

  @param error

  Optional error to associate with the close operation

  @returns

  Number of bytes written or a Promise resolving to the number of bytes

• flush(): number | Promise<number>;

  Flush the internal buffer, committing the data to disk or the pipe.

  @returns

  Number of bytes flushed or a Promise resolving to the number of bytes

• ref(): void;

  For FIFOs & pipes, keep Bun's process alive until the pipe closes.

  By default, this is managed automatically: while the stream is open the process stays alive, and once the other end hangs up or the stream closes, the process exits.

  If you previously called unref, call this to re-enable automatic management.

  Internally, calls to ref and unref are reference counted. The count starts at 1.

  If the file is not a FIFO or pipe, ref and unref do nothing. If the pipe is already closed, this does nothing.

• start(

  options?: { highWaterMark: number }

  ): void;

  Start the file sink with provided options.

  @param options

  Configuration options for the file sink

• unref(): void;

  For FIFOs & pipes, allow Bun's process to exit while the stream is open.

  If the file is not a FIFO or pipe, ref and unref do nothing. If the pipe is already closed, this does nothing.

• write(

  chunk: string | ArrayBuffer | SharedArrayBuffer | ArrayBufferView<ArrayBufferLike>

  ): number | Promise<number>;

  Write a chunk of data to the file.

  If the file descriptor is not writable yet, the data is buffered.

  @param chunk

  The data to write

  @returns

  Number of bytes written or, if the write is pending, a Promise resolving to the number of bytes