Creating a tree from a flat list using lodash
Your code is very imperative. Try focusing on the "big picture" of data flow instead of writing code by trial-and-error. It's harder, but you get better results (and, in fact, usually it's faster) :)
My idea is to first group the categories by their parents. This is the first line of my solution and it actually becomes much easier after that.
_.groupBy and _.keyBy help a lot here:
function makeCatTree(data) {
var groupedByParents = _.groupBy(data, 'parent');
var catsById = _.keyBy(data, 'id');
_.each(_.omit(groupedByParents, ''), function(children, parentId) {
catsById['c' + parentId].children = children;
});
_.each(catsById, function(cat) {
// isParent will be true when there are subcategories (this is not really a good name, btw.)
cat.isParent = !_.isEmpty(cat.children);
// _.compact below is just for removing null posts
cat.children = _.compact(_.union(cat.children, cat.posts));
// optionally, you can also delete cat.posts here.
});
return groupedByParents[''];
}
I recommend trying each part in the developer console, then it becomes easy to understand.
I have made a small fidde that I think that is what you want.
http://jsfiddle.net/tx3uwhke/
var tree = buildTree(getData());
var pre = document.getElementById('a');
var jsonString = JSON.stringify(tree, null, 4);
console.log(jsonString);
pre.innerHTML = jsonString;
document.body.appendChild(pre);
function buildTree(data, parent){
var result = [];
parent = typeof parent !== 'undefined' ? parent : {id:""};
children = _.filter(data, function(value){
return value.parent === parent.id;
});
if(!_.isEmpty(children)){
_.each(children, function(child){
if (child != null){
result.push(child);
if(!_.isEmpty(child.posts)){
var posts = _.filter(child.posts, function(post){
return post !== null && typeof post !== 'undefined';
});
if(!_.isEmpty(posts)){
_.forEach(posts, function(post){
post.isParent = false;
});
}
result = _.union(result, posts);
delete child.posts;
}
ownChildren = buildTree(data, child);
if(!_.isEmpty(ownChildren)){
child.isParent = true;
child.children = ownChildren;
}else{
child.isParent = false;
}
}
});
}
return result;
}EDIT: made a new fiddle to contain the isParent part you can find it here