Road to

Majid Hajian

mhadaily

import 'package:flutter/material.dart';
MaterialApp(
   ThemeData(
        name: "Majid Hajian",
        location: "Oslo, Norway",
        description: '''
                Google Developer Expert
        	Passionate Software engineer, 
	        Community Leader, Author and international Speaker
         ''',
        main: "Head of DevRel at Invertase.io",
        homepage: "https://www.majidhajian.com",
        socials: {
          twitter: "https://www.twitter.com/mhadaily",
          github: "https://www.github.com/mhadaily"
        },
        author: {
          Pluralsight: "www.pluralsight.com/authors/majid-hajian",
          Apress: "Progressive Web App with Angular, Book",
          PacktPub: "PWA development",
          Udemy: "PWA development",
        }
        founder: "Softiware As (www.Softiware.com)"
        devDependencies: {
          tea: "Ginger", 
          mac: "10.14+",
        },
        community: {
          FlutterVikings: "Orginizer", 
          FlutterCommunity: "Admin/Lead",
          ...more
        },
        ),
       );

mhadaily

Find me on the internet by

Head of DevRel at Invertase

Majid Hajian

final speakerJson = {
  "name": "Majid",
  "age": 25,
  "active": true,
};

List<dynamic> getSpeaker(json) {
  return [
    json['name'] as String,
    json['age'] as int,
    json['active'] as bool,
  ];
}

main() {
  final speaker = getSpeaker(speakerJson);
  final name = speaker[0];
  final age = speaker[1];
  final active = speaker[2];
}

mhadaily

class Speaker {
  Speaker(this.name, this.age, this.active);
  final String name;
  final int age;
  final bool active;
}

Speaker getSpeaker(json) {
  return Speaker(
    json['name'] as String,
    json['age'] as int,
    json['active'] as bool,
  );
}
main() {
  final speaker = getSpeaker(speakerJson);
  print(speaker.name);
  print(speaker.age);
  print(speaker.active);
}

mhadaily

class Speaker {
  Speaker(this.name, this.age, this.active);
  final String name;
  final int age;
  final bool active;
  factory Speaker.fromJson(json) {
    return Speaker(
      json['name'] as String,
      json['age'] as int,
      json['active'] as bool,
    );
  }
}

main() {
  final speaker = Speaker.fromJson(speakerJson);
  print(speaker.name);
  print(speaker.age);
  print(speaker.active);
}

mhadaily

var record = ('first', a: 2, b: true, 'last');

(String, int, bool) getSpeaker(json) {
  return (
    json['name'] as String,
    json['age'] as int,
    json['active'] as bool,
  );
}

main() {
  final speaker = getSpeaker(speakerJson);
  final name = speaker.$1;
  final age = speaker.$2;
  final active = speaker.$3;
}

Records

mhadaily

(String, int, bool) getSpeaker(json) {
  return (
    json['name'] as String,
    json['age'] as int,
    json['active'] as bool,
  );
}

main() {
  final (name, age, active) = getSpeaker(speakerJson);
  print(name);
  print(age);
  print(active);
}

Patterns

mhadaily




({String name, int age, bool active}) getSpeaker(json) {
  return (
    name: json['name'],
    age: json['age'],
    active: json['active'],
  );
}

main() {
  final speaker = getSpeaker(speakerJson);
  final name = speaker.name;
  final age = speaker.age;
  final active = speaker.active;
}

Records

mhadaily





({String name, int age, bool active}) getSpeaker(json) {
  return (
    name: json['name'],
    age: json['age'],
    active: json['active'],
  );
}

main() {
  final (:name, :age, :active) = getSpeaker(speakerJson);
  print('$name, $age, $active');
}

Patterns

mhadaily





({String name, int age, bool active}) getSpeaker(json) {
  return (
    name: json['name'],
    age: json['age'],
    active: json['active'],
  );
}

main() {
  final (name: name1) = getSpeaker(speakerJson);
  print(name1);

  final (name, _) = ("Majid", 25);
  print(name);
}

Patterns

mhadaily





final json = {'speaker':  ['Majid', 25]};

Patterns

mhadaily





main() {
  final json = {'speaker': ['Majid', 25]};

  final        {'speaker': [name,    age]} = json;

  print('$name, $age'); // Majid, 25
}

Patterns

mhadaily





if (json is Map<String, Object?> &&
    json.length == 1 &&
    json.containsKey('user')) {
  var user = json['user'];
  if (user is List<Object> &&
      user.length == 2 &&
      user[0] is String &&
      user[1] is int) {
    var name = user[0] as String;
    var age = user[1] as int;
    print('User $name is $age years old.');
  }
}

If

mhadaily



main() {
  final json = {
    'speaker': ['Majid', 25]
  };

  if (json case {'speaker': [String name, int age]}) {
    print('valid json!');
  }
}

Switch/If

mhadaily

main() {
  final json = {
    'speaker': ['Majid', 25]
  };

  switch (json) {
    case {'speaker': [String name, int age]}:
      print('valid json!');
    default:
      print('invalid');
  }
}

Switch/If

mhadaily

main() {
  final json = {
    'speaker': ['Majid', 25]
  };

  final int customAge = 25;

  switch (json) {
    case {'speaker': [String name, int age]} when customAge == age:
      print('valid json!');
    default:
      print('invalid');
  }
}

Switch/If

mhadaily

main() {
  final json = {
    'speaker': ['Majid', 25]
  };

  final int customAge = 25;

  switch (json) {
    case {'speaker': [String name, customAge && int age]}:
      print('valid json!');
    default:
      print('invalid');
  }
}

Switch/If

mhadaily

ThemeData getTheme(ThemeMode mode) {
  switch (mode) {
    case ThemeMode.light:
      return ThemeData.light();
    case ThemeMode.dark:
      return ThemeData.dark();
    default:
      return ThemeData.light();
  }
}

ThemeData getTheme(ThemeMode mode) {
  if (mode == ThemeMode.light) {
      return ThemeData.light();
  }
  if(mode == ThemeMode.dark){
      return ThemeData.dark();
  }
  return ThemeData.light();
}

Switch/If

mhadaily






ThemeData getTheme(ThemeMode mode) {
  switch (mode) {
  	
    ThemeMode.light => ThemeData.light(),
    ThemeMode.dark => ThemeData.dark(),
  }
}

Switch/If

mhadaily





(Color textColor, Brightness brightness) getThemeSettings(mode) {
  return switch (mode) {
    ThemeMode.light => (Colors.white, Brightness.light),
    ThemeMode.dark => (Colors.black, Brightness.dark),
    _ => throw Error()
  };
}

final (textColor, brightness) = getThemeSettings(ThemeMode.dark);

Switch/If

mhadaily

import 'package:flutter/material.dart';
void main() => runApp(
      MaterialApp(
        debugShowCheckedModeBanner: false,
        home: Scaffold(
          body: Center(
            child: FutureBuilder(
              future: Future<String>.delayed(
                const Duration(seconds: 3),
                () => 'Hello World!',
              ),
              builder: (context, snapshot) => switch (snapshot) {
                (AsyncSnapshot s) when s.hasData => Text(s.data!),
                (AsyncSnapshot s) when !s.hasError =>
                  const CircularProgressIndicator.adaptive(),
                (_) => const Text('Error'),
              },
            ),
          ),
        ),
      ),
    );

Flutter

mhadaily

import 'package:flutter/material.dart';
void main() => runApp(
      MaterialApp(
        debugShowCheckedModeBanner: false,
        home: Scaffold(
          body: Center(
            child: FutureBuilder(
              future: Future<String>.delayed(
                const Duration(seconds: 3),
                () => 'Hello World!',
              ),
              builder: (context, snapshot) => switch (snapshot) {
                AsyncSnapshot(:final data) => Text(s.data),
                (AsyncSnapshot s) when !s.hasError =>
                  const CircularProgressIndicator.adaptive(),
                (_) => const Text('Error'),
              },
            ),
          ),
        ),
      ),
    );

Flutter

mhadaily

class AuthException implements Exception {}
class EmailAlreadyInUseException extends AuthException {
  EmailAlreadyInUseException(this.email);
  final String email;
}
class WeakPasswordException extends AuthException {}
class WrongPasswordException extends AuthException {}
class UserNotFoundException extends AuthException {}


String describe(AuthException exception) {
  switch (exception) {
    case EmailAlreadyInUseException():
      return 'Email already in use';
    case WeakPasswordException():
      return 'Password is too weak';
    case WrongPasswordException():
      return 'Wrong password';
    case UserNotFoundException():
      return 'User not found';
    default:
      return 'Unknown exception';
  }
}

mhadaily

class AuthException implements Exception {}
class EmailAlreadyInUseException extends AuthException {
  EmailAlreadyInUseException(this.email);
  final String email;
}
class WeakPasswordException extends AuthException {}
class WrongPasswordException extends AuthException {}
class UserNotFoundException extends AuthException {}


String describe(AuthException exception) {
  return switch (exception) {
    EmailAlreadyInUseException(:var email) => 'Email already in use: $email',
    WeakPasswordException() => 'Password is too weak',
    WrongPasswordException() => 'Wrong password',
    _ => 'Unknown exception',
  };
}

main() {
  print(describe(EmailAlreadyInUseException('m@mj.com')));
}

mhadaily

sealed class AuthException implements Exception {}
class EmailAlreadyInUseException extends AuthException {
  EmailAlreadyInUseException(this.email);
  final String email;
}
class WeakPasswordException extends AuthException {}
class WrongPasswordException extends AuthException {}
class UserNotFoundException extends AuthException {}


String describe(AuthException exception) {
  return switch (exception) {
    EmailAlreadyInUseException(:var email) => 'Email already in use: $email',
    WeakPasswordException() => 'Password is too weak',
    WrongPasswordException() => 'Wrong password',
  };
}

main() {
  print(describe(EmailAlreadyInUseException('m@mj.com')));
}

mhadaily

dart.dev/language

mhadaily

Find me on the internet by

Head of DevRel at Invertase

Majid Hajian

Slides

slides.com/mhadaily

Road to Dart 3

By Majid Hajian

Road to Dart 3

Majid Hajian

Majid Hajian is a passionate software developer with years of developing and architecting complex web and mobile applications. He is passionate about web platform especially flutter, IoT, PWAs, and performance.

Road to

mhadaily

Records

Patterns

Records

Patterns

Patterns

Patterns

Patterns

If

Switch/If

Switch/If

Switch/If

Switch/If

Switch/If

Switch/If

Switch/If

Flutter

Flutter

mhadaily

Road to Dart 3

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