javascript - Creating array of nested objects from array of non nested objects -

suppose have following array:

[      {         'id':48,       'parent':0,       'order':1    },    {         'id':49,       'parent':48,       'order':2    },    {         'id':50,       'parent':0,       'order':3    },    {         'id':51,       'parent':48,       'order':4    },    {         'id':52,       'parent':0,       'order':5    },    {         'id':53,       'parent':50,       'order':6    },    {         'id':54,       'parent':50,       'order':7    } ] 

i need write javascript code either in angular controller or using ng-repeat in view can produce following output:

  [      {         'id':48,       'parent':0,       'order':1,       'children':[            {               'id':49,             'parent':48,             'order':2          },          {               'id':51,             'parent':48,             'order':4          }       ]    },    {         'id':50,       'parent':0,       'order':3,       'children':[            {               'id':53,             'parent':50,             'order':6          },          {               'id':54,             'parent':50,             'order':7          }       ]    },    {         'id':52,       'parent':0,       'order':5    },  ] 

you can assume original array sorted order already, output have maintain order well.

my current solution work. i'm using ng-repeat conditional argument check if current object has parent.

essentially i'm using ng-repeat output parents, loop through entire array again each parent checking children. has severe performance penalties , takes long array on 40-50 objects long. downside each depth, performance penalties increase. include 5 nesting levels, looping system not hold up.

ideally, sort out in controller, , make ng-repeat minimal work.

did read current solution? here is, since i'm being accused of getting things free eye roll

<div class="comments">         <span></span>         <ul>             <li class="comment byuser comment-author-solopine bypostauthor thread-even depth-1" id="comment-21">                 <span></span>                 <div class="thecomment">                     <span></span>                     <div class="author-img">                         <span><img alt="" class="avatar avatar-60 photo" height="60" src="{{%20comment.author_avatar_urls['96']%20}}" width="60"></span>                     </div><span></span>                     <div class="comment-text">                         <span><span class="reply"><a class="comment-reply-link scroll" href="" rel="nofollow">reply</a></span></span>                         <h6 class="author">{{ comment.author_name }}</h6><span class="date">{{ comment.date | date : 'longdate' }}</span>                         <p></p>                         <div></div>                         <p></p>                     </div>                 </div>             </li>             <li style="list-style: none">                 <span></span>                 <ul class="children">                     <li class="comment byuser comment-author-solopine bypostauthor odd alt depth-2" id="comment-24">                         <span></span>                         <div class="thecomment">                             <span></span>                             <div class="author-img">                                 <span><img alt="" class="avatar avatar-60 photo" height="60" src="{{%20childcomment.author_avatar_urls['96']%20}}" width="60"></span>                             </div><span></span>                             <div class="comment-text">                                 <span><span class="reply"><a class="comment-reply-link" href="" rel="nofollow">reply</a></span></span>                                 <h6 class="author">{{ childcomment.author_name }}</h6><span class="date">{{ childcomment.date | date : 'longdate' }}</span>                                 <p></p>                                 <div></div>                                 <p></p>                             </div>                         </div>                     </li><!-- #comment-## -->                 </ul><!-- .children -->                 <!-- #comment-## -->             </li>         </ul>     </div> 

as said, using ng-repeat.

you coud use object lookup , insert parent's children. adn node itself.

this proposal works if parent inserted before children.

var data = [{ 'id': 48, 'parent': 0, 'order': 1 }, { 'id': 49, 'parent': 48, 'order': 2 }, { 'id': 50, 'parent': 0, 'order': 3 }, { 'id': 51, 'parent': 48, 'order': 4 }, { 'id': 52, 'parent': 0, 'order': 5 }, { 'id': 53, 'parent': 50, 'order': 6 }, { 'id': 54, 'parent': 50, 'order': 7 }],      tree = [];    data.foreach(function (a) {      this[a.id] = { id: a.id, parent: a.parent, order: a.order };      this[a.parent].children = this[a.parent].children || [];      this[a.parent].children.push(this[a.id]);  }, { 0: { children: tree } });    console.log(tree);

proposal unsorted data witch maintains sort order.

var data = [{ 'id': 54, 'parent': 50, 'order': 7 }, { 'id': 53, 'parent': 50, 'order': 6 }, { 'id': 49, 'parent': 48, 'order': 2 }, { 'id': 51, 'parent': 48, 'order': 4 }, { 'id': 52, 'parent': 0, 'order': 5 }, { 'id': 48, 'parent': 0, 'order': 1 }, { 'id': 50, 'parent': 0, 'order': 3 }, ],      tree = function (data) {          var r = [], o = { 0: { children: r } };          data.foreach(function (a) {              var p = 0,                  temp = { id: a.id, parent: a.parent, order: a.order };              if (o[a.id] && o[a.id].children) {                  temp.children = o[a.id].children;              }              o[a.id] = temp;              o[a.parent] = o[a.parent] || {};              o[a.parent].children = o[a.parent].children || [];                                  o[a.parent].children.some(function (a) {                                          if (a.order > temp.order) {                      return true;                  }                  p++;              });              o[a.parent].children.splice(p, 0, temp);          });          return r;      }(data);    console.log(tree);