Q:

Accessing deeper array keys

I am trying to create a navigation menu which supports dropdown items.  I have created
var menuItems={
items:[
{
    title:"Home",
    id:1
},
{
    title:"Download App",
    children:["iOS","Android","Windows"],
    id:2
},
{
    title:"About",
    id:3
}
]
};

This is my Menu Prototype Class:
var MenuProto = React.createClass({
render: function(){
    return <li><a>{this.props.title}</a>
      <ul className="dropdown-menu">
        <li><a>{this.props.children}</a></li>
      </ul>
    </li>
}
});

And this is where it is called:
var Menu = React.createClass({
  render : function(){
    var fullmenu = this.props.items.map(function(item){
       return <MenuProto {...item}/>
    });
    return <ul className="nav navbar-nav navbar-right">
       {fullmenu}
    </ul>
  }
});

Apparently this.props.children gets all the array and uses renders it on the menu while I need it to get them one by one.  I have tried creating a var similar to fullmenu which would iterate through childrens of this.props.children one by one but I can't figure out how. 
I would also need a hint on how to make a conditional to see if an object has or doesnt have the children key. 
Any help would be greatly appreciated. 

A:

You can iterate on this.props.children using the React. Children utilities:
var MenuProto = React.createClass({
render: function(){
    return <li><a>{this.props.title}</a>
      <ul className="dropdown-menu">
        {React. Children.map(this.props.children, function(child) {
          return <li key={child.id}><a>{child.title}</a></li>
        })}
      </ul>
    </li>
}
});

Since you want to support nested items, you'll need some additional custom logic. 
You can check to see if an object has a children key by simply testing for the existence of whatever.children; if it doesn't have that key, it will be a falsy value (specifically undefined).