@blocknote/core/src/api/blockManipulation/commands/nestBlock/nestBlock.ts

A "Notion-style" block-based extensible text editor built on top of Prosemirror and Tiptap.

import { Fragment, NodeType, Slice } from "prosemirror-model";
import { Transaction } from "prosemirror-state";
import { ReplaceAroundStep } from "prosemirror-transform";

import { BlockNoteEditor } from "../../../../editor/BlockNoteEditor.js";
import { getBlockInfoFromTransaction } from "../../../getBlockInfoFromPos.js";

// TODO: Unit tests
/**
 * This is a modified version of https://github.com/ProseMirror/prosemirror-schema-list/blob/569c2770cbb8092d8f11ea53ecf78cb7a4e8f15a/src/schema-list.ts#L232
 *
 * The original function derives too many information from the parentnode and itemtype
 */
function sinkListItem(
  tr: Transaction,
  itemType: NodeType,
  groupType: NodeType,
) {
  const { $from, $to } = tr.selection;
  const range = $from.blockRange(
    $to,
    (node) =>
      node.childCount > 0 &&
      (node.type.name === "blockGroup" || node.type.name === "column"), // change necessary to not look at first item child type
  );
  if (!range) {
    return false;
  }
  const startIndex = range.startIndex;
  if (startIndex === 0) {
    return false;
  }
  const parent = range.parent;
  const nodeBefore = parent.child(startIndex - 1);
  if (nodeBefore.type !== itemType) {
    return false;
  }
  const nestedBefore =
    nodeBefore.lastChild && nodeBefore.lastChild.type === groupType; // change necessary to check groupType instead of parent.type
  const inner = Fragment.from(nestedBefore ? itemType.create() : null);
  const slice = new Slice(
    Fragment.from(
      itemType.create(null, Fragment.from(groupType.create(null, inner))), // change necessary to create "groupType" instead of parent.type
    ),
    nestedBefore ? 3 : 1,
    0,
  );

  const before = range.start;
  const after = range.end;

  tr.step(
    new ReplaceAroundStep(
      before - (nestedBefore ? 3 : 1),
      after,
      before,
      after,
      slice,
      1,
      true,
    ),
  ).scrollIntoView();

  return true;
}

export function nestBlock(editor: BlockNoteEditor<any, any, any>) {
  return editor.transact((tr) => {
    return sinkListItem(
      tr,
      editor.pmSchema.nodes["blockContainer"],
      editor.pmSchema.nodes["blockGroup"],
    );
  });
}

export function unnestBlock(editor: BlockNoteEditor<any, any, any>) {
  editor._tiptapEditor.commands.liftListItem("blockContainer");
}

export function canNestBlock(editor: BlockNoteEditor<any, any, any>) {
  return editor.transact((tr) => {
    const { bnBlock: blockContainer } = getBlockInfoFromTransaction(tr);

    return tr.doc.resolve(blockContainer.beforePos).nodeBefore !== null;
  });
}

export function canUnnestBlock(editor: BlockNoteEditor<any, any, any>) {
  return editor.transact((tr) => {
    const { bnBlock: blockContainer } = getBlockInfoFromTransaction(tr);

    return tr.doc.resolve(blockContainer.beforePos).depth > 1;
  });
}