Panchin's questions

I was doing a test service and from my component when calling the service and wanting to add ".subscribe" it gave me an error that the method was not an observable...

Searching the internet, I managed to solve the problem if I added something like this to my service using .map:

loadAll() {
    return this.http.get(this.url)
        .map(res => res.json());            
}

When adding .map from the component if ".subscribe" worked fine for me.

What I don't understand is what that .map does, I googled but couldn't find any info.

According to what the visual studio code shows me (in English) it is something that takes a result and creates an observable... Could you please clarify what this .map does?

Thank you very much

I have seen that in angular 2 instead of using ngModel I can put something like this:

<input type="text" name="txtnombre" #Nombre />
<button (click) = "validarNombre(#Nombre)" > Validar </ button>

I don't quite understand when to use this type of variable with # and what is the advantage of using this instead of this

<input type="text" name="txtnombre" [(ngModel)]="nombre" />

Could someone explain to me? Thank you.