JS: Flatten tree

index.js

import React from "react";
import ReactDOM from "react-dom";
import tree from "./Tree.json";

const flattenTree = tree => {
  let newData = [];

  const flattenFn = (node) => {
    if (node.child && node.child.length) {
      node.child.forEach(subNode => {
        flattenFn(subNode);
      });
    }

    const newNode = { ...node };
    delete newNode.child;
    newData.push(newNode);
  };

  flattenFn(tree);

  return newData;
};

const output = JSON.stringify(flattenTree(tree), null, "  ");
const rootElement = document.getElementById("root");
ReactDOM.render(<pre>{output}</pre>, rootElement);

Tree.json

{
  "id": 1,
  "name": "sample 1",
  "child": [
    {
      "id": 12,
      "name": "sample 12",
      "child": [],
      "parentId": 1
    },
    {
      "id": 13,
      "name": "sample 13",
      "child": [],
      "parentId": 1
    },
    {
      "id": 14,
      "name": "sample 14",
      "child": [],
      "parentId": 1
    },
    {
      "id": 2,
      "name": "sample 2",
      "child": [
        {
          "id": 22,
          "name": "sample 22",
          "parentId": 2,
          "child": [
            {
              "id": 222,
              "name": "sample 222",
              "child": [],
              "parentId": 22
            },
            {
              "id": 223,
              "name": "sample 223",
              "child": [],
              "parentId": 22
            },
            {
              "id": 224,
              "name": "sample 224",
              "parentId": 22,
              "child": [
                {
                  "id": 2242,
                  "name": "here dito",
                  "child": [],
                  "parentId": 224
                },
                {
                  "id": 2232,
                  "name": "sample 2232",
                  "child": [],
                  "parentId": 224
                },
                {
                  "id": 2244,
                  "name": "sample 2244",
                  "child": [],
                  "parentId": 224
                }
              ]
            }
          ]
        },
        {
          "id": 23,
          "name": "sample 23",
          "child": [],
          "parentId": 2
        },
        {
          "id": 24,
          "name": "sample 24",
          "child": [],
          "parentId": 2
        }
      ]
    }
  ]
}