dart_gists_future.dart

import 'package:http/http.dart' as http;
import 'dart:convert';
import 'dart:io';
import 'dart:async';

class Gists{
    // instance variable for user
    String user;
    Future getGistsForUser(String user){
      this.user = user; 
      var url = "https://api.github.com/users/${this.user}/gists";
      return http.get(url)
        .then((res) => _processResults(res))
        .catchError(_handleError);
    }
      
    _processResults(http.Response jsonString){
      List<String> items = JSON.decode(jsonString.body);
      var res = [];
      items.forEach((element) => res.add(element["html_url"]));
      return res;
    }
      
    _handleError(Error error){
      print("User ${this.user} not available");
    }
}

void main() {
    Gists gists = new Gists();
    stdout.writeln('Enter your GitHub username');
    String username = stdin.readLineSync();
    gists.getGistsForUser(username)
        .then((res) => print(res.join("\n")))
        .catchError((error) => print(error.toString()));
}