jsTree的问题，请大神指点。不懂什么意思

Question

$('#jstree_demo').jstree({
"core" : {
"animation" : 0,
"check_callback" : true,
"themes" : { "stripes" : true },
'data' : {
'url' : function (node) {
return node.id === '#' ?
'ajax_demo_roots.json' : 'ajax_demo_children.json';
},
'data' : function (node) {
return { 'id' : node.id };
}
}
},
"types" : {
"#" : {
"max_children" : 1,
"max_depth" : 4,
"valid_children" : ["root"]
},
"root" : {
"icon" : "/static/3.3.1/assets/images/tree_icon.png",
"valid_children" : ["default"]
},
"default" : {
"valid_children" : ["default","file"]
},
"file" : {
"icon" : "glyphicon glyphicon-file",
"valid_children" : []
}
},
"plugins" : [
"contextmenu", "dnd", "search",
"state", "types", "wholerow"
]
});