Function splitByNotebooks

packages/convert/src/snapshot/split.ts:238–293

(file: DeepnoteFile, sourceFileStem: string)

/** Splits a multi-notebook DeepnoteFile into one file per notebook, emitting the init notebook (if any) as a standalone entry first. */
export function splitByNotebooks(file: DeepnoteFile, sourceFileStem: string): NotebookSplitEntry[] {
  const notebooks = file.project.notebooks
  if (notebooks.length === 0) {
    return []
  }

  const initNotebookId = file.project.initNotebookId
  const initNotebook = initNotebookId === undefined ? undefined : notebooks.find(nb => nb.id === initNotebookId)

  // A file containing only the init notebook is already in single-notebook form.
  if (initNotebook !== undefined && notebooks.length === 1) {
    return []
  }

  const used = new Set<string>()
  const result: NotebookSplitEntry[] = []

  if (initNotebook !== undefined) {
    const initFilename = allocateUniqueNotebookSplitFilename(sourceFileStem, initNotebook.name, used)
    result.push({
      notebook: { id: initNotebook.id, name: initNotebook.name },
      file: {
        ...file,
        project: {
          ...file.project,
          notebooks: [initNotebook],
        },
      },
      outputFilename: initFilename,
    })
  }

  const mainNotebooks = initNotebook === undefined ? notebooks : notebooks.filter(nb => nb.id !== initNotebook.id)
  if (mainNotebooks.length === 0) {
    // A standalone init entry alone is not useful.
    return []
  }

  // Drop an initNotebookId matching no notebook here; left dangling it would make `deepnote run` fail sibling-init resolution.
  const hasDanglingInit = initNotebookId !== undefined && initNotebook === undefined

  for (const notebook of mainNotebooks) {
    const outputFilename = allocateUniqueNotebookSplitFilename(sourceFileStem, notebook.name, used)
    const project = { ...file.project, notebooks: [notebook] }
    if (hasDanglingInit) {
      delete project.initNotebookId
    }
    result.push({
      notebook: { id: notebook.id, name: notebook.name },
      file: { ...file, project },
      outputFilename,
    })
  }

  return result
}