How to correctly collect a nested object without specifying a parent?

Question

JavaScript

Hello! There is a tree in the form of an array with an indication of the nesting level, you need to make an array from it with nested objects.
The input is the following array:

[
{id:1, title: 'test1', level:0},
{id:2, title: 'test2', level:1},
{id3, title: 'test3', level:2},
{id:4, title: 'test4', level:1},
{id:5, title: 'test5', level:0},
]

the output should be like this:

[
{
   id:1,
   title: 'test1',
   nodes: [
      {
          id:2,
          title: 'test2',
         nodes: [
             id: 3,
             title: 'test3'
             nodes: []
        ]
      },
      {
          id:4,
          title: 'test4',
          nodes: []
      }
   ],
   {
       id:5,
       title: 'test5',
       nodes: []
   }
}
]

Answer 1

function getNested(data, idField, parentField, rootParent) {
  const
    root = [],
    obj = {};

  data.forEach(n => obj[n[idField]] = Object.assign({ nodes: [] }, n));

  Object.values(obj).forEach(n => {
    if (n[parentField] == rootParent) {
      root.push(n);
    } else {
      obj[n[parentField]].nodes.push(n);
    }
  });

  return root;
}

const nested = getNested([
  {id:1, title: 'test1', level:0},
  {id:2, title: 'test2', level:1},
  {id:3, title: 'test3', level:2},
  {id:4, title: 'test4', level:1},
  {id:5, title: 'test5', level:0},
], 'id', 'level', 0);