<undefined> html tag getting generated in angular2 beta 0 app

Question

I am currently using the latest angular.beta.0 and have followed their quick start tutorial with the router tutorial. The app works fine but upon inspecting the generated DOM, there is an <undefined> tag generated. It isnt causing any issues but I would want it to be clarified.

The undefined tag contains the whole app markup in it.

Answer 1

When Routing you can skip the selector in the components, which is valid. But they will appear as undefined. That may look ugly, so you can avoid it by specifying a selector which will work as a name and won't match any custom element in your templates.

So this will produce an undefined custom element in your DOM

// Some component loaded through routing    
@Component({
    // No selector!
    template : 'Some template'
})

This will not

// Some component loaded through routing    
@Component({
    selector : 'some-component',
    template : 'Some template'
})

This case will show some-component in the DOM instead of undefined.

I hope it helps.