@atlaskit/editor-plugin-list/dist/es2019/pm-plugins/actions/indent-list.js

List plugin for @atlaskit/editor-core

import { Fragment, Slice } from '@atlaskit/editor-prosemirror/model';
import { ReplaceAroundStep } from '@atlaskit/editor-prosemirror/transform';

// adapted from https://github.com/ProseMirror/prosemirror-schema-list/blob/master/src/schema-list.js#L206:L231
export const indentList = tr => {
  const {
    $from,
    $to
  } = tr.selection;
  const {
    listItem
  } = tr.doc.type.schema.nodes;
  const range = $from.blockRange($to, node => !!node.childCount && !!node.firstChild && node.firstChild.type === listItem);
  if (!range) {
    return false;
  }

  // get the index of the selected list item in the list it is part of
  const startIndex = range.startIndex;
  if (startIndex === 0) {
    return false;
  }

  // get the parent list of the list item(s) in the selected range
  const parent = range.parent;

  // get the list immediately before the selection start
  const previousListItem = parent.child(startIndex - 1);
  if (previousListItem.type !== listItem) {
    return false;
  }

  // if that list was nested, join the selected list items into the same
  // nested list; if not, create a new child list of the same type and
  // nest it under the current level
  const isPreviousListNested = previousListItem.lastChild && ['bulletList', 'orderedList'].includes(previousListItem.lastChild.type.name);
  const inner = Fragment.from(isPreviousListNested ? listItem.create() : undefined);
  // Ignored via go/ees005
  // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
  // Ignored via go/ees005
  // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
  const nextListNodeType = isPreviousListNested ? previousListItem.lastChild.type : parent.type;
  const nextListNodeContent = Fragment.from(nextListNodeType.create(null, inner));
  const slice = new Slice(Fragment.from(listItem.create(null, nextListNodeContent)), isPreviousListNested ? 3 : 1, 0);
  const before = range.start;
  const after = range.end;
  tr.step(new ReplaceAroundStep(before - (isPreviousListNested ? 3 : 1), after, before, after, slice, 1, true));
};