@atlaskit/editor-plugin-paste-options-toolbar/dist/es2019/ui/utils/paste-menu-rules/hasMixedNodes.js

Paste options toolbar for @atlaskit/editor-core

/**
 * Structural container nodes are nodes whose children are determined by
 * document structure (e.g. list items inside a list, rows inside a table)
 * rather than by content choice. Having different child types inside these
 * nodes does NOT indicate mixed content.
 *
 * All other container nodes (blockTaskItem, blockquote, panel,
 * expand, layoutColumn, tableCell, tableHeader, bodiedExtension, etc.) hold
 * rich block content, so mixed block children inside them IS mixing.
 */
const STRUCTURAL_CONTAINERS = new Set(['bulletList', 'orderedList', 'listItem', 'taskList', 'decisionList', 'table', 'tableRow']);

/**
 * Returns true if a node's direct block-level children include more than one
 * distinct node type — i.e. the children are "mixed".
 */
const hasBlockSiblings = node => {
  const types = new Set();
  node.forEach(child => {
    if (child.isBlock) {
      types.add(child.type.name);
    }
  });
  return types.size > 1;
};

/**
 * Returns true if the slice contains sibling block nodes of different types
 * at the same level anywhere in the document tree.
 *
 * Structural container nodes (bulletList, orderedList, taskList, decisionList,
 * table, tableRow) are excluded from the sibling check because their children
 * are typed by structure, not content. All other container nodes are checked.
 */
export const hasMixedNodes = slice => {
  var _slice$content;
  if (!(slice !== null && slice !== void 0 && (_slice$content = slice.content) !== null && _slice$content !== void 0 && _slice$content.size)) {
    return false;
  }

  // Check the top-level children of the slice (Fragment has no parent Node,
  // so we construct a synthetic check by iterating slice.content directly).
  const topLevelTypes = new Set();
  slice.content.forEach(node => {
    if (node.isBlock) {
      topLevelTypes.add(node.type.name);
    }
  });
  if (topLevelTypes.size > 1) {
    return true;
  }

  // Walk every descendant node and check its direct block children for mixing,
  // skipping structural containers (their children are structural, not content).
  let mixed = false;
  slice.content.descendants(node => {
    if (mixed) {
      return false; // short-circuit once found
    }
    if (STRUCTURAL_CONTAINERS.has(node.type.name)) {
      return true; // recurse into but don't check children for mixing
    }
    if (hasBlockSiblings(node)) {
      mixed = true;
      return false;
    }
    return true;
  });
  return mixed;
};