List of nodes with ancestors and corresponding tree structure with children.

ancestor_list_child_tree.rb

nodes = [
  {id: '1',    ancestor_ids: []},
  {id: '12',   ancestor_ids: ['1']},
  {id: '13',   ancestor_ids: ['1']},
  {id: '124',  ancestor_ids: ['1','12']},
  {id: '125',  ancestor_ids: ['1','12']},
  {id: '136',  ancestor_ids: ['1','13']},
  {id: '1367', ancestor_ids: ['1','13','136']},
  {id: '1368', ancestor_ids: ['1','13','136']},
  {id: '19',   ancestor_ids: ['1']}
]


tree = {
  id: '1', children: [
    {id: '19', children:[]},
    {id: '12', children:[
      {id: '124', children: []},
      {id: '125', children: []}
    ]},
    {id: '13', children:[
      {id: '136', children: [
        {id: '1367', children:[]},
        {id: '1368', children:[]}
      ]}
    ]}
  ]
}