Function runAndSaveExport

runAndSaveExport(
    writable: SaveFileWritable | null,
    run: (
        onChunk?: (data: Uint8Array) => Promise<void>,
    ) => Promise<ExportStreamResult>,
    saveBlob?: (blob: Blob, fileName: string) => void,
): Promise<ExportStreamResult>
Runs an export and saves it: into writable, chunk by chunk, when the user chose a file, otherwise through a download link once the export completes.

With a file, run gets a chunk consumer that writes to it; pass that on as downloadExportViaNats's onChunk, so each write finishes before its chunk is acknowledged. The file is closed when the export completes. If the export or a write fails, or the export is cancelled, the file is aborted instead, which discards what was written; a file that was being replaced stays as it was.
Parameters
- writable: SaveFileWritable | null
  The chosen file, or null to save through a download link.
- run: (onChunk?: (data: Uint8Array) => Promise<void>) => Promise<ExportStreamResult>
  Starts the export, passing onChunk on to the download (it is undefined without a file, and the result's Blob is saved instead).
- saveBlob: (blob: Blob, fileName: string) => void = saveBlobViaLink
  Saves the Blob; saveBlobViaLink unless a test passes one.
Returns Promise<ExportStreamResult>
The export result.

Throws
Whatever the export, a write or closing the file throws.
- Defined in plot/export-sink.ts:116