Solution to Navigator Question

stack2.dart

//Author: Owamoyo Evans - lordvidex
//Email: lordvidex.prime@gmail.com
//GitHub: https://github.com/lordvidex

import 'package:flutter/material.dart';
//Logic on third page
void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      debugShowCheckedModeBanner: false,
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: FirstPage(),
      routes: {
        SecondPage.routeName: (_)=>SecondPage(),
        ThirdPage.routeName: (_)=>ThirdPage(),
      },
    );
  }
}

class FirstPage extends StatelessWidget {
 static const routeName = '/';
  @override
  Widget build(BuildContext context) {
     void _nextPage(){
    Navigator.of(context).pushNamed(SecondPage.routeName);
  }

    return Scaffold(
      appBar: AppBar(
        title: Text('First Page'),
      ),
      body: Center(
        child: Text('First Page'),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: _nextPage,
        child: Icon(Icons.add),
      ),
    );
  }
}
class SecondPage extends StatelessWidget{
  static const routeName = '/second';
  @override
  Widget build(BuildContext context){
    void _nextPage(){
    Navigator.of(context).pushNamed(ThirdPage.routeName);
  }
    return Scaffold(
      appBar: AppBar(
        title: Text('Second Page'),
      ),
      body: Center(
        child: Text('Second Page'),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: _nextPage,
        child: Icon(Icons.add),
      ),
    );
  }
}

class ThirdPage extends StatelessWidget{
  static const routeName = '/third';
  @override
  Widget build(BuildContext context){
    void _nextPage(){
      //Logic here - ***************************
   Navigator.of(context).popUntil((Route<dynamic> route) => route.isFirst);
  }
    return Scaffold(
      appBar: AppBar(
        title: Text('Third Page'),
      ),
      body: Center(
        child: Text('Third Page'),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: _nextPage,
        child: Icon(Icons.add),
      ),
    );
  }
}