How to pass data from children to parent in a tree object?

Question

JavaScript

Good afternoon, there is such an object in the array

[
  {
    "id": 1,
    "parentid": null,
    "count": "0",
    "children": [
      {
        "id": 2,
        "parentid": 1,
        "count": "89",
        "children": [
          {
            "id": 3,
            "parentid": 2,
            "count": "19",
            "children": [
              {
                "id": 5,
                "parentid": 3,
                "count": "205"
              },
              {
                "id": 4,
                "parentid": 3,
                "count": "8"
              }
            ]
          }
        ]
      }
    ]
  }
]

I need to pass the count value from the children to each parent above, does anyone know the solution?

Answer 1

Recursively traverse the entire tree in depth and calculate for each element the data on its descendants.

Answer 2

At the same time, the original tree should remain unchanged?