Clean Code - Dart Examples

!clean_code.md

All the code examples from my Clean Code series are here.

Clean Code Youtube Playlist Link Click Here

Clean Code Book reference: https://amzn.to/3BVggeJ

a_save_method.dart

// Choose meaningful names

// ❌ Bad:
void save() { }

// ✅ Good:
void saveCustomerIntoDatabase() { }

b_length_of_a_name.dart

// The Length of a Name

// Variables

List<int> studentsGrades = [9, 8, 15, 21];

var gradesSum = 0;
// the index can be called just "i" because the scope is small (one line)
for (int i = 0; i < studentsGrades.length; i++) {
  gradesSum = gradesSum + studentsGrades [i];
}

// Functions or Classes Name

// For Functions and Classes it's the opposite, for smaller scopes the function 
// name should be big (very explanatory)

void updateUsersAvatarColor() { }

// For larger scopes the Function or Class should have a smaller name
User getUser() { }

c_searchable_names.dart

// Choose searchable names


// ❌ Bad:
var h = 300;

// ✅ Good:
var eiffelTowerHeight = 300;

d_negative_names.dart

// Avoid negative names


// ❌ Bad (negative word):
if (cartIsNotEmpty) {
 // ...
} else {
 // ...
}

// ✅ Good (positive word): 
if (cartIsFull) {
 // ...
} else {
 // ...
}

e_negative_statements.dart

// Avoid negative statements

// ❌ Bad (negative if):
if (!cartIsFull) {
 // ...
} else {
 // ...
}

// ✅ Good (positive word): 
if (cartIsFull) {
 // ...
} else {
 // ...
}

f_prefixes.dart

// Don’t use prefixes
// Choose names you can pronounce

// ❌ Bad:
var dateDMY;

// ✅ Good:
var dateDayMonthYearFormat;

g_optical_illusions.dart

// Be careful with optical illusions

// ❌ Bad:
var textFieldNameController;
var textFieldUsernameController;

// ✅ Good:
var nameTextFieldController;
var usernameTextFieldController;

h_meaningful_distinction.dart

// Make meaningful distinction between names


// ❌ Bad:
class Product { }
class ProductData { }
class ProductInfo { }

// ✅ Good:
class Product { } // Only one class for Product

i_copyrights_acceptable_comments.dart

// There are some types of comments that are acceptable, like:

//  ✅ copyrights

// Copyright (c) 2019, the Dart project authors.  Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

import 'package:flutter/material.dart';

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: const MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}

j_informative_comments_acceptable_comments.dart

// Acceptable comments

//  ✅  informative comments explaining a pattern (for example regEx)

void main() {
  final email = '[email protected]';
  // Checks:
  // if the email has at and dot signs
  // if it has characters before and after the at sign
  // if it has characters after the dot sign
  final regExp = RegExp(r"^[\w-\.]+@([\w-]+\.)+[\w-]{2,4}$");

  if (regExp.hasMatch(email)) {
    print('Email válido!');
  } else {
    print('Email inválido!');
  }
}

k_warning_of_consequences_acceptable_comments.dart

// Acceptable comments

//  ✅ warning of consequences

void main() {

// DON'T RUN THESE TESTS UNLESS YOU HAVE SOME TIME TO KILL
test ('test 1', () {}); 
test ('test 2', () {});
test ('test 3', () {}); 
test ('test 4', () {}); 
// [...]
test ('test 20', () {}); 
test ('test 21', () {}); 
}

l_todo_comments_acceptable_comments.dart

// Acceptable comments

//  ✅ TODO comments, but try to not leave them when you leave the code, they are probably going to be forgotten

// TODO: Call the API to get this data

m_public_apis_acceptable_comments.md

// Acceptable comments

// ✅ Public APIs

n_bad_comments.dart

// Bad types of comments

// ❌ Bad (Redundant comments):

// This is the main function
void main() { }

// ❌ Bad:
// Comments to version control (use git instead)

// ❌ Bad:
// Commented code

// ❌ Bad:
// Comments about a code that is somewhere else


// But more importantly: you should only use comments when you fail to make your code express itself.

Thank for sharing 🤗 @LeBaleiro