Knockout.js nested model and observable arrays -


i'm new knockout , have problems @ beginning. consider following model:

// @param {string} content content of post // @param {number} reply_to id indicating post post replying // @param {array} replies array of discussionposts indicating replies post  var discussionpost(content, reply_to, replies) {     var self = this;     self.content = content;     self.reply_to = reply_to;     self.replies = ko.observablearray(         ko.utils.arraymap(replies, function(reply) {             return new discussionpost(reply.content, reply.reply_to, reply.replies);         })  }

now view model, consider have posts in flat array called allposts , try build structure previous model follows:

var rootposts = allposts.filter(function (o) {     return o.reply_to === null; }); var result = (function iterate(posts) {     var tree = [];     $.each(posts, function(i, post){         var replies = allposts.filter(function(o) {             return o.reply_to === post.id;         });         if (replies.length > 0) {             replies = iterate(replies);         }          var tmppost = new discussionpost(post.content, post.reply_to, replies);         tree.push(tmppost);     });     return tree; })(rootposts);

theoretically, result variable shall contain graph of posts posts don't have parent @ root. instance following tree shall return array 1 element i.e.the root, replies should c1 , c2 , array replies of c1 shall contain c3. problem root filled expected, , replies c1 , c2, replies of c1 returns array 4 elements of type discussionpost properties (content, reply_to, , replies) undefined. if instead of knockouts' observable array use regular javascript array in model works fine @ 100 level deep. 

    root     / \     /   \   c1   c2  / c3

how non-recursive approach? 

function discussionpost(post) {     var self = this;     self.content = ko.observable(post.content);     self.reply_to = ko.observable(post.reply_to);     self.replies = ko.observablearray([]); }  var result = (function (posts) {     var index = {}, root = "null";      // root level     index[root] = new discussionpost({});      // transform discussionpost objects, index id     ko.utils.arrayforeach(posts, function (post) {         index[post.id] = new discussionpost(post);      });      // build tree     ko.utils.arrayforeach(posts, function (post) {         if (post.reply_to in index) {             index[post.reply_to].replies.push(index[post.id]);         } else {             // orphaned post         }     });      return index[root].replies; })(allposts);

this should perform nicer larger numbers of posts. it's easier read , debug approach.


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