Problem calling variable in constructor


#1

How can I call a variable in a constructor?

constructor ( private auth: AngularFireAuth ) {
this.auth.authState.subscribe((user)=> {this.email = user.email});

this.url = 'http://localhost/check.php' + this.email;  
// **CALLIG this.email DOESN"T WORK. HOW CAN I MAKE IT WORK?**
..........
..........
}

#2