How to get parent object property in child

I have a javascript object like below:

{
 type: "ul",
 id: "1",
 children: [
  {
   type: "li",
   id: "2",
   children: [
    {
      type: "ul",
      id: "3",
      children: [...]
    }
   ]
  }
 ]
}

I want to turn it into:

{
 type: "ul",
 id: "1",
 children: [
  {
   type: "li",
   id: "2",
   parentId: "1",
   children: [
    {
      type: "ul",
      id: "3",
      parentId: "2",
      children: [...]
    }
   ]
  }
 ]
}

There can be infinite nesting in the children’s array and it should add parentId to only who have a parent and stop if the children’s array is empty or the key doesn’t exists

>Solution :

Here’s a recursive solution:

const obj={type:"ul",id:"1",children:[{type:"li",id:"2",children:[{type:"ul",id:"3"}]}]};

function setIds(obj, parent) {
    if (parent) {
      obj.parentId = parent.id;
    }
    obj?.children?.forEach(e => setIds(e, obj))
}

setIds(obj)
console.log(obj)

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