Playing with JSON in dart. :)

JSONplay.dart

/// JSONplay.dart
/// Playing with JSON in dart. :)
/// https://gist.github.com/JoeCodeswell/864394a7d86087113a7ad2ef2d80d542
/// https://dartpad.dev/864394a7d86087113a7ad2ef2d80d542
/// google: dart json
///   [Using JSON](https://dart.dev/guides/json)
///     [dart:convert - decoding and encoding JSON, UTF-8, and more](https://dart.dev/guides/libraries/library-tour#dartconvert---decoding-and-encoding-json-utf-8-and-more)
///       [dart:convert library](https://api.dart.dev/stable/2.8.4/dart-convert/dart-convert-library.html)
///         [How to parse Json in Flutter for Beginners](https://medium.com/flutter-community/how-to-parse-json-in-flutter-for-beginners-8074a68d7a79)
///   [JSON and serialization](https://flutter.dev/docs/development/data-and-backend/json)
///   [flutter cookbook Parse JSON in the background](https://flutter.dev/docs/cookbook/networking/background-parsing)
/// 
///   google: 
///     "dart json" stinks
///     dart instantiate class from "json list"
///     [JSON to Dart](https://javiercbk.github.io/json_to_dart/)
///       [github](https://github.com/javiercbk/json_to_dart)
///         [Convert the response into a list of photos](https://flutter.dev/docs/cookbook/networking/background-parsing#convert-the-response-into-a-list-of-photos)
///           [Complete example](https://flutter.dev/docs/cookbook/networking/background-parsing#complete-example)
///     [2 Months of Flutter Development](https://dev.to/irosthebeggar/2-months-of-flutter-development-2gi5)
///     [General serialization for Dart objects.](https://github.com/google/serialization.dart)
/// 
/// See VERY HELPFUL ANSWERS IN [Mapping JSON into Class Objects](https://stackoverflow.com/a/45189401/601770)
import 'dart:convert';

import 'dart:convert';

void main() {
  print(itmLstr.runtimeType); // String
  var itmLstrJsDec = json.decode(itmLstr);
  print(itmLstrJsDec.runtimeType); // JSArray<dynamic>
  print(itmLstrJsDec[0].runtimeType); // _JsonMap 
  print(itmLstrJsDec[0]); // {name: Sarah, age: 19, role: Student}
  
  assert(itmLstrJsDec[0] is Map );
  // errors Undefined Names; [name, age, role]
  // var jsonmap = {name: Sarah, age: 19, role: Student}; 
  // JSArray<Map> joes_item_list_json_decode2 = json.decode(joes_item_list); // error unknown type JSArray
  
  // [Complete example](https://flutter.dev/docs/cookbook/networking/background-parsing#complete-example)
  /*
  // A function that converts a response body into a List<Photo>.
List<Photo> parsePhotos(String responseBody) {
  final parsed = jsonDecode(responseBody).cast<Map<String, dynamic>>();

  return parsed.map<Photo>((json) => Photo.fromJson(json)).toList();
}
*/
  List<JdiJsL> parseJdiJsLs(String responseBody) {
    final parsed = jsonDecode(responseBody).cast<Map<String, dynamic>>();
    return parsed.map<JdiJsL>((json) => JdiJsL.fromJson(json)).toList();
  }
  
  var myJdiJsL = parseJdiJsLs(itmLstr);
  print(myJdiJsL[0].name); // Sarah
  
  print('');
  for (var itm in myJdiJsL){
    print('${itm.name} ${itm.age} ${itm.role}  ' );
  }
  print('');
  /* output
  Sarah 19 Student  
  Janine 43 Professor  
  William 27 Associate Professor  
  Frances 37 Student  
  Maxine 29 Student  
  Jennifer 25 Student  
  Joe 49 Adjunct Professor  
  */
  
  myJdiJsL.add(JdiJsL(name: 'Jim', age: 32, role: 'Lab Tech'));
  myJdiJsL.add(JdiJsL(name: 'Darcy', age: 21, role: 'Student'));
  for (var itm in myJdiJsL){
    print('${itm.name} ${itm.age} ${itm.role}  ' );
  }  
  print('');

  var myJdiJsLjson =  jsonEncode(myJdiJsL);
  print(myJdiJsLjson);
  print('');
//   var decoded = JSON.decode('["foo", { "bar": 499 }]');
//   var decoded = jsonDecode('["foo", { "bar": 499 }]');
//   var deaths6061_PlacerCounty_CA = JSON.decode(
  var deaths6061_PlacerCounty_CA = jsonDecode(
  '''{
    "type":"deaths",
    "countyFIPS": 6061,
    "county": "Placer County",
    "state": "CA",
    "fromDate": "2020,08,01",
    "thruDate": "2020,08,08",
    "valList": [
      {"date":"2020,08,01", "value": 15},
      {"date":"2020,08,02", "value": 16},
      {"date":"2020,08,03", "value": 17},
      {"date":"2020,08,04", "value": 18},
      {"date":"2020,08,05", "value": 19},
      {"date":"2020,08,06", "value": 20},
      {"date":"2020,08,07", "value": 20},
      {"date":"2020,08,08", "value": 20}
    ]
   }'''
  );
print('${deaths6061_PlacerCounty_CA["type"]}');  
print('${deaths6061_PlacerCounty_CA["county"]}');  
  for (var ix in [0,1,2,3,4,5,6,7]){
    print('${deaths6061_PlacerCounty_CA["valList"][ix]}');  
  }
} // main

var itmLstr = '''[
{"name":"Sarah", "age":19, "role":"Student" },
  {"name":"Janine", "age":43, "role":"Professor" },
  {"name":"William", "age":27, "role":"Associate Professor" },
  {"name":"Frances", "age":37, "role":"Student" },
  {"name":"Maxine", "age":29, "role":"Student" },
  {"name":"Jennifer", "age":25, "role":"Student" },
  {"name":"Joe", "age":49, "role":"Adjunct Professor" }
]''';



/// https://javiercbk.github.io/json_to_dart/
///   https://github.com/javiercbk/json_to_dart
class JdiJsL {
  String name;
  int age;
  String role;

  JdiJsL({this.name, this.age, this.role});

  JdiJsL.fromJson(Map<String, dynamic> json) {
    name = json['name'];
    age = json['age'];
    role = json['role'];
  }

  Map<String, dynamic> toJson() {
    final Map<String, dynamic> data = new Map<String, dynamic>();
    data['name'] = this.name;
    data['age'] = this.age;
    data['role'] = this.role;
    return data;
  }
}
/* Console output
String
JSArray<dynamic>
_JsonMap
{name: Sarah, age: 19, role: Student}
Sarah

Sarah 19 Student  
Janine 43 Professor  
William 27 Associate Professor  
Frances 37 Student  
Maxine 29 Student  
Jennifer 25 Student  
Joe 49 Adjunct Professor  

Sarah 19 Student  
Janine 43 Professor  
William 27 Associate Professor  
Frances 37 Student  
Maxine 29 Student  
Jennifer 25 Student  
Joe 49 Adjunct Professor  
Jim 32 Lab Tech  
Darcy 21 Student  

[{"name":"Sarah","age":19,"role":"Student"},{"name":"Janine","age":43,"role":"Professor"},{"name":"William","age":27,"role":"Associate Professor"},{"name":"Frances","age":37,"role":"Student"},{"name":"Maxine","age":29,"role":"Student"},{"name":"Jennifer","age":25,"role":"Student"},{"name":"Joe","age":49,"role":"Adjunct Professor"},{"name":"Jim","age":32,"role":"Lab Tech"},{"name":"Darcy","age":21,"role":"Student"}]

deaths
Placer County
{date: 2020,08,01, value: 15}
{date: 2020,08,02, value: 16}
{date: 2020,08,03, value: 17}
{date: 2020,08,04, value: 18}
{date: 2020,08,05, value: 19}
{date: 2020,08,06, value: 20}
{date: 2020,08,07, value: 20}
{date: 2020,08,08, value: 20}
*/