How to get these varibales out side from the method angular 2

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Typescript

Hello im new to ionic 2 and also for anguar 2.Here is my code for login using firebase.I used foreach method in firebase documentation.in here
The thing is how i can return the key and child data to global variables?
if i use console.log it will show the correct value but i can't find a way to get the values out and pass it to next page.
Any suggestions??

Thank You

What I have tried:

Login(){
  
  let x = this.tyindexno;
  let y =this.typassword;
var query = this.userlistRef.orderByKey();
query.once("value",function(snapshot) {
    snapshot.forEach(function(childSnapshot) {
      var key = childSnapshot.key;
      if(key==x){
      // Cancel enumeration
      console.log(key);
      var childData = childSnapshot.val();
      
      if(childData.password==y){
     console.log(childData.password);
      }
      return true;
    }   
  });
})
}