{
  "-KhWrBcYyMluJbK7QpnK" : {
    "Info" : {
      "Email" : "xyz@gmail.com"
    },
    "Settings" : {
      "Status" : "Accepted"
    }
  },
  "-KhX0tgQvDtDYqt4XRoL" : {
    "Info" : {
      "Email" : "abc@abc.com"
    },
    "Settings" : {
      "Status" : "Accepted"
    }
  },
  "-KhX1eo7uFnOxqncDXQ5" : {
    "Info" : {
      "Email" : "abc@abc.com"
    },
    "Settings" : {
      "Status" : "Pending"
    }
  }
}

"Invitation" : {
   ".indexOn": ["Info/Email","Settings/Status"]
}

var rootRef = firebase.database().ref().child('Invitation');
var userInvitations = rootRef.child("Info").orderByChild("Email").equalTo("abc@abc.com");
var allInvitations = $firebaseArray(userInvitations);

{
  "-KhWrBcYyMluJbK7QpnK" : {
    "Email" : "xyz@gmail.com",
    "Settings" : {
      "Status" : "Accepted"
    }
  },
  "-KhX0tgQvDtDYqt4XRoL" : {
    "Email" : "abc@abc.com",
    "Settings" : {
      "Status" : "Accepted"
    }
  },
  "-KhX1eo7uFnOxqncDXQ5" : {
    "Email" : "abc@abc.com",
    "Settings" : {
      "Status" : "Pending"
    }
  }
}

"Invitation" : {
   "Info" : {
      ".indexOn": "Email",
   },
   "Settings" : {
      ".indexOn": "Status",
   }
}

var allInvitations = [];
var rootRef = firebase.database().ref().child('Invitation');
var userInvitations = rootRef.orderByChild("Email").equalTo("abc@abc.com");
userInvitations.on('value', snap => {
    var invitations =  snap.val()
    for (prop in invitations ) {
     allInvitations.push(invitations[prop ]);

    }
    console.log(allInvitations);

})