jEasyUI tree menu loads parent/child nodes

The usual way to represent a tree node is to store a parentid in each node. This is also known as the adjacency list model. Directly loading these data into the tree menu (Tree) is not allowed. But we can convert the tree menu into the standard tree menu (Tree) data format before loading it. The Tree plug-in provides a 'loadFilter' option function, which can implement this function. It provides an opportunity to change any incoming data. This tutorial shows you how to load parent/child nodes into a Tree using the 'loadFilter' function.

Parent/child node data

	[
	{"id":1,"parendId":0,"name":"Foods"},
	{"id":2,"parentId":1,"name":"Fruits"},
	{"id":3,"parentId":1,"name":"Vegetables"},
	{"id":4,"parentId":2,"name":"apple"},
	{"id":5,"parentId":2,"name":"orange"},
	{"id":6,"parentId":3,"name":"tomato"},
	{"id":7,"parentId":3,"name":"carrot"},
	{"id":8,"parentId":3,"name":"cabbage"},
	{"id":9,"parentId":3,"name":"potato"},
	{"id":10,"parentId":3,"name":"lettuce"}
	]

Use 'loadFilter' to create a tree menu (Tree)

	$('#tt').tree({
		url: 'data/tree6_data.json',
		loadFilter: function(rows){
			return convert(rows);
		}
	});

Conversion implementation

	function convert(rows){
		function exists(rows, parentId){
			for(var i=0; i<rows.length; i++){
				if (rows[i].id == parentId) return true;
			}
			return false;
		}
		
		var nodes = [];
		// get the top level nodes
		for(var i=0; i<rows.length; i++){
			var row = rows[i];
			if (!exists(rows, row.parentId)){
				nodes.push({
					id:row.id,
					text:row.name
				});
			}
		}
		
		var toDo = [];
		for(var i=0; i<nodes.length; i++){
			toDo.push(nodes[i]);
		}
		while(toDo.length){
			var node = toDo.shift();	// the parent node
			// get the children nodes
			for(var i=0; i<rows.length; i++){
				var row = rows[i];
				if (row.parentId == node.id){
					var child = {id:row.id,text:row.name};
					if (node.children){
						node.children.push(child);
					} else {
						node.children = [child];
					}
					toDo.push(child);
				}
			}
		}
		return nodes;
	}

Download jQuery EasyUI example

jeasyui-tree-tree6.zip