How to add an object to a nested javascript object using a parent id

Question

In my application I create a JavaScript object based on a JSON response from the server similar to this:

{
  name: "root",
  id: 1,
  children: [
    {
      name: "child one",
      id: 11,
      children: [
       {name: "grand child 1", id: 111, children: []},
       {name: "grand child 2", id: 112, children: []}
      ]
   },
   {
     name: "child two",
     id: 12,
     children: []
   }
  ]
}

I create a new node such as:

 {name: "grandchild three", id: 113, children:[]}

With this in mind, how can I add this new grandchild to its parent with id 11? Please note that I don’t know the static path to node with id == 11 so I am wondering how I could obtain that node with just knowing it's id.

Edit: please note the id's in the real case do NOT encode the path to objects. I created this simple example for demonstration of the data structure I am dealing with. But I can not retrieve the path to the object using its id in my real application.

Answer 1

See this fiddle: http://jsfiddle.net/2Dvws/

It will find an object by ID. And push the new child. Since every object within Javascript is a reference, you can return it as an var.

var ob = {
    name: "root",
    id: 1,
    children: [
        {
        name: "child one",
        id: 11,
        children: [
            {
            name: "grand child 1",
            id: 111,
            children: []},
        {
            name: "grand child 2",
            id: 112,
            children: []}
        ]},
    {
        name: "child two",
        id: 12,
        children: []}
    ]
};

The function which will return the found element. Will look into all child elements.

function findObjectById(root, id) {
    if (root.children) {
        for (var k in root.children) {
            if (root.children[k].id == id) {
                return root.children[k];
            }
            else if (root.children.length) {
                return findObjectById(root.children[k], id);
            }
        }
    }
};

var bla = findObjectById(ob, 111);

console.log(bla);
bla.children.push({
        name: "child x",
        id: 1111,
        children: []
});
console.log(ob);

Output is that child with id 111 will have 1 child with id 1111 ​