Hierarchical tree view

I want to create a hierarchical from my MySql data response, it has jsut id and sponsor_id. I am not sure how to start, please help me solving this

[ { "id": 2723021, "sponsor_id": "2723020" }, { "id": 2723022, "sponsor_id": "2723021" }, { "id": 2723023, "sponsor_id": "2723021" }, { "id": 2723024, "sponsor_id": "2723021" }, { "id": 2723025, "sponsor_id": "2723022" }, { "id": 2723026, "sponsor_id": "2723022" }, { "id": 2723027, "sponsor_id": "2723022" }, { "id": 2723028, "sponsor_id": "2723023" }, { "id": 2723029, "sponsor_id": "2723023" }, { "id": 2723030, "sponsor_id": "2723023" }, { "id": 2723031, "sponsor_id": "2723024" }, { "id": 2723032, "sponsor_id": "2723024" }, { "id": 2723033, "sponsor_id": "2723024" }, { "id": 2723034, "sponsor_id": "2723025" } ]

I want to make it like this

Nothing coming in my mind what & how to start

Solution

Just create a map by item id, and find parents and add children to them, if no parent is found it's the root item.

const arr = [ { "id": 2723021, "sponsor_id": "2723020" }, { "id": 2723022, "sponsor_id": "2723021" }, { "id": 2723023, "sponsor_id": "2723021" }, { "id": 2723024, "sponsor_id": "2723021" }, { "id": 2723025, "sponsor_id": "2723022" }, { "id": 2723026, "sponsor_id": "2723022" }, { "id": 2723027, "sponsor_id": "2723022" }, { "id": 2723028, "sponsor_id": "2723023" }, { "id": 2723029, "sponsor_id": "2723023" }, { "id": 2723030, "sponsor_id": "2723023" }, { "id": 2723031, "sponsor_id": "2723024" }, { "id": 2723032, "sponsor_id": "2723024" }, { "id": 2723033, "sponsor_id": "2723024" }, { "id": 2723034, "sponsor_id": "2723025" } ]


const map = arr.reduce((r, item) => (r[item.id] = item, r), {});
let root;
Object.values(map).forEach(item => {
  const parent = map[item.sponsor_id];
  parent ? (parent.children ??= []).push(item) : root = item;
});

console.log(root);

A simpler version:

const arr = [ { "id": 2723021, "sponsor_id": "2723020" }, { "id": 2723022, "sponsor_id": "2723021" }, { "id": 2723023, "sponsor_id": "2723021" }, { "id": 2723024, "sponsor_id": "2723021" }, { "id": 2723025, "sponsor_id": "2723022" }, { "id": 2723026, "sponsor_id": "2723022" }, { "id": 2723027, "sponsor_id": "2723022" }, { "id": 2723028, "sponsor_id": "2723023" }, { "id": 2723029, "sponsor_id": "2723023" }, { "id": 2723030, "sponsor_id": "2723023" }, { "id": 2723031, "sponsor_id": "2723024" }, { "id": 2723032, "sponsor_id": "2723024" }, { "id": 2723033, "sponsor_id": "2723024" }, { "id": 2723034, "sponsor_id": "2723025" } ]


const map = {};
for(const item of arr) map[item.id] = item;
let root;
for(const id in map){
  const item = map[id];
  const parent = map[item.sponsor_id];
  if(parent){
    if(!parent.children) parent.children = [];
    parent.children.push(item);
  }else{
    root = item;
  }
}

console.log(root);