Tree Hierarchy parent-child from array of objects

Approach2.js

console.time("execution");
var posts = [{
		"id": 1,
		"name": "Earth",
		"children": [2, 3]
	}, {
		"id": 2,
		"name": "Asia",
		"children": []
	}, {
		"id": 4,
		"name": "Germany",
		"children": [5]
	}, {
		"id": 3,
		"name": "Europe",
		"children": [4, 8]
	},
	{
		"id": 5,
		"name": "Hamburg",
		"children": [7]
	},
	{
		"id": 6,
		"name": "Mars",
		"children": []
	},
	{
		"id": 7,
		"name": "Stellingen",
		"children": []
	},
	{
		"id": 8,
		"name": "Itali",
		"children": [9]
	},
	{
		"id": 9,
		"name": "Rome",
		"children": []
	}
];


var tree = function (array) {
        var r = {},
            children = new Set,
            result = [];

        array.forEach(o => {
            Object.assign(
                r[o.id] = r[o.id] || {},
                o,
                { children: o.children.map(id => (children.add(id), r[id] = r[id] || {})) }
            );
        });
        return Object.values(r).filter(({ id }) => !children.has(id));
    }(posts);

console.log(JSON.stringify(tree));
console.timeEnd("execution");

TREE Approach1.js

console.time("execution");
var posts = [{
		"id": 1,
		"name": "Earth",
		"children": [2, 3]
	}, {
		"id": 2,
		"name": "Asia",
		"children": []
	}, {
		"id": 4,
		"name": "Germany",
		"children": [5]
	}, {
		"id": 3,
		"name": "Europe",
		"children": [4, 8]
	},
	{
		"id": 5,
		"name": "Hamburg",
		"children": [7]
	},
	{
		"id": 6,
		"name": "Mars",
		"children": []
	},
	{
		"id": 7,
		"name": "Stellingen",
		"children": []
	},
	{
		"id": 8,
		"name": "Itali",
		"children": [9]
	},
	{
		"id": 9,
		"name": "Rome",
		"children": []
	}
];


var discardables = [];

function getIndexOfById(id, posts) {
	for(var i = 0; i < posts.length; i++){
		if(posts[i].id == id) {
			return i;
		}
	}
}

function discardUsedChilds (newPosts) {
	for(var i in discardables) {
		var index = getIndexOfById(discardables[i], newPosts)
		newPosts.splice(index, 1);
	}
}
function getElementById (id, posts) {
	for(var i =0; i< posts.length; i++){
		if(posts[i].id === id){
			
			discardables.push(id);
			return posts[i];
		}
	}
} 

function refactorChildren(element, posts) {
  if(!element.children || element.children.length === 0) {
    return element;
  }
  
  var children = [];
  for(var i = 0; i < element.children.length; i++){
    var childElement = getElementById(element.children[i], posts);    
    children.push(childElement);
  }
  element.children = children;
  
  return element;
}

function iterate(posts) {
  var newPosts = [];
  var des = [...posts]
  for(var i = 0; i < des.length; i++){
    var childedElement = refactorChildren(des[i], des);
     newPosts.push(childedElement);
  }
  discardUsedChilds(newPosts)
  return (newPosts);
}


var filtered = iterate(posts);
console.log(JSON.stringify(filtered))
console.timeEnd("execution");