Teach you how to refactor PHP code better

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Release: 2023-04-11 10:52:01
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This article brings you relevant knowledge about PHP, and mainly talks about what is refactoring? How to better refactor PHP code? Friends who are interested can take a look below. I hope it will be helpful to everyone.

Teach you how to refactor PHP code better

Refactoring refers to modifying or rewriting the code without changing the original functionality.

In the following examples, I will show you how to write better code.

#1 - Expressiveness

This may just be a simple tip, but writing expressive code can greatly improve our code. Always make the code self-explanatory so that future you or other developers can know what is going on in the code.

However, some developers say that naming is one of the most difficult things in programming. That's one reason why it's not as easy as it sounds.

Example #1 - Naming

Before

// ❌ 这个方法是用来做什么的,方法名表达并不清晰
// ❌ 是设置状态还是检查状态呢?
$status = $user->status('pending');
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After

// ✅ 通过添加 is,使方法名表达的意图更清晰
// ✅ 检测用户状态是否与给定状态相等
// ✅ 同时新变量名让我们可以推断它是布尔值
$isUserPending = $user->isStatus('pending');
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Example #2 - Naming

before

// ❌ 这个类返回的是什么?类名?类全名?还是类路径?
return $factory->getTargetClass();
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after

// ✅ 我们获取的是类路径
// ✅ 如果用户想要类名?则找错了方法
return $factory->getTargetClassPath();
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Example #3 - Extract

before

// ❌ 重复的代码 ( "file_get_contents", "base_path" 方法以及文件扩展)
// ❌ 此刻,我们不去关心如何获得code examples
public function setCodeExamples(string $exampleBefore, string $exampleAfter)
{
    $this->exampleBefore = file_get_contents(base_path("$exampleBefore.md"));
    $this->exampleAfter = file_get_contents(base_path("$exampleAfter.md"));
}
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after

public function setCodeExamples(string $exampleBefore, string $exampleAfter)
{ 
    // ✅ 代码直接说明了我们的意图:获取code example(不关注如何获取)
    $this->exampleBefore = $this->getCodeExample($exampleBefore);
    $this->exampleAfter = $this->getCodeExample($exampleAfter);
}
// ✅ 这个新方法可多次调用
private function getCodeExample(string $exampleName): string
{
    return file_get_contents(base_path("$exampleName.md"));
}
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Example #4 - Extract

Before

// ❌ 多重 where 语句,使阅读变得困难
// ❌ 意图究竟是什么呢?
User::whereNotNull('subscribed')->where('status', 'active');
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After

// ✅ 这个新的scope方法说明了发生了什么事
// ✅ 如果我们需要了解更多细节,可以进入这个scope方法内部去了解
// ✅ "subscribed" scope 方法可在其他地方使用
User::subscribed();
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Example #5 - Extract

This is an example from my previous project. We use the command line to import users. The ImportUsersCommand class contains a handle method to handle tasks.

Before

protected function handle()
{
    // ❌ 这个方法包含太多代码
    $url = $this->option('url') ?: $this->ask('Please provide the URL for the import:');
    $importResponse =  $this->http->get($url);
    // ❌ 进度条对用户很有用,不过却让代码显得杂乱
    $bar = $this->output->createProgressBar($importResponse->count());
    $bar->start();
    $this->userRepository->truncate();
    collect($importResponse->results)->each(function (array $attributes) use ($bar) {
        $this->userRepository->create($attributes);
        $bar->advance();
    });
    // ❌ 很难说清此处发生了哪些行为
    $bar->finish();
    $this->output->newLine();
    $this->info('Thanks. Users have been imported.');
    if($this->option('with-backup')) {
        $this->storage
            ->disk('backups')
            ->put(date('Y-m-d').'-import.json', $response->body());
        $this->info('Backup was stored successfully.');
    }
}
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After

protected function handle(): void
{
    // ✅ handle方法是你访问该类首先会查看的方法
    // ✅ 现在可以很容易就对这个方法做了些什么有个粗略的了解
    $url = $this->option('url') ?: $this->ask('Please provide the URL for the import:');
    $importResponse =  $this->http->get($url);
    $this->importUsers($importResponse->results);
    $this->saveBackupIfAsked($importResponse);
}
// ✅ 如果需要了解更多细节,可以查看这些专用的方法
protected function importUsers($userData): void
{
    $bar = $this->output->createProgressBar(count($userData));
    $bar->start();
    $this->userRepository->truncate();
    collect($userData)->each(function (array $attributes) use ($bar) {
        $this->userRepository->create($attributes);
        $bar->advance();
    });
    $bar->finish();
    $this->output->newLine();
    $this->info('Thanks. Users have been imported.');
}
// ✅ 不要害怕使用多行代码
// ✅ 这个例子中它让我们核心的 handle 方法更为简洁
protected function saveBackupIfAsked(Response $response): void
{
    if($this->option('with-backup')) {
        $this->storage
            ->disk('backups')
            ->put(date('Y-m-d').'-import.json', $response->body());
        $this->info('Backup was stored successfully.');
    }
}
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#2 - Early return

Early return means that we try to pass the structure Decompose into specific cases to avoid nesting. This way we get a more linear code that is easier to read and understand. Don't be afraid to use multiple return statements.

Example#1

Before

public function calculateScore(User $user): int
{
    if ($user->inactive) {
        $score = 0;
    } else {
        // ❌ 怎么又有一个 "if"?
        if ($user->hasBonus) {
            $score = $user->score + $this->bonus;
        } else {
            // ❌ 由于存在多个层级,大费眼神 ? 
            $score = $user->score;
        }
    }
    return $score;
}
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After

public function calculateScore(User $user): int
{
    // ✅ 边缘用例提前检测
    if ($user->inactive) {
        return 0;
    }
    // ✅ 每个用例都有自己的代码块,使得更容易跟进
    if ($user->hasBonus) {
        return $user->score + $this->bonus;
    }
    return $user->score;
}
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Example#2

Before

public function sendInvoice(Invoice $invoice): void
{
    if($user->notificationChannel === 'Slack')
    {
        $this->notifier->slack($invoice);
    } else {
        // ❌ 即使是简单的ELSE都影响代码的可读性
        $this->notifier->email($invoice);
    }
}
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After

public function sendInvoice(Invoice $invoice): bool
{
    // ✅ 每个条件都易读
    if($user->notificationChannel === 'Slack')
    {
        return $this->notifier->slack($invoice);
    }
    // ✅ 不用再考虑ELSE 指向哪里
    return $this->notifier->email($invoice);
}
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Note: Sometimes you will hear the term "defense statement", which is implemented by returning early.

#3 - Reconstruct into a collection Collection

In PHP, we use arrays in many different data. The functionality available for handling and converting these arrays is very limited and does not provide a good experience. (array_walk, usort, etc)

To deal with this problem, there is a concept of Collection class that can be used to help you deal with arrays. The best known implementation is in Laravel, where the collection class provides many useful features for working with arrays.

Note: In the following examples, I will use Laravel's collect () helper function, but it can be used in similar ways in other frameworks or libraries.

Example#1

Before

// ❌ 这里我们有一个临时变量 
$score = 0;
// ❌ 用循环没有问题,不过可读性还是有改善空间
foreach($this->playedGames as $game) {
    $score += $game->score;
}
return $score;
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After

// ✅ 集合是带有方法的对象
// ✅ sum 方法使之更具表现力
return collect($this->playedGames)
    ->sum('score');
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Example#2

Before

$users = [
    [ 'id' => 801, 'name' => 'Peter', 'score' => 505, 'active' => true],
    [ 'id' => 844, 'name' => 'Mary', 'score' => 704, 'active' => true],
    [ 'id' => 542, 'name' => 'Norman', 'score' => 104, 'active' => false],
];
// 请求结果: 只显示活跃用户,以 score 排序  ["Mary(704)","Peter(505)"]
$users = array_filter($users, fn ($user) => $user['active']);
// ❌ usort 进行排序处理的又是哪一个对象呢?它是如何实现?
usort($users, fn($a, $b) => $a['score'] < $b['score']);
// ❌ 所有的转换都是分离的,不过都是users相关的
$userHighScoreTitles = array_map(fn($user) => $user['name'] . '(' . $user['score'] . ')', $users);
return $userHighScoreTitles;
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After

$users = [
    [ 'id' => 801, 'name' => 'Peter', 'score' => 505, 'active' => true],
    [ 'id' => 844, 'name' => 'Mary', 'score' => 704, 'active' => true],
    [ 'id' => 542, 'name' => 'Norman', 'score' => 104, 'active' => false],
];
// 请求结果: 只显示活跃用户,以 score 排序  ["Mary(704)","Peter(505)"]
// ✅ 只传入一次users
return collect($users)
    // ✅ 我们通过管道将其传入所有方法
  ->filter(fn($user) => $user['active'])
  ->sortBy('score')
  ->map(fn($user) => "{$user['name']} ({$user['score']})"
  ->values()
    // ✅ 最后返回数组
  ->toArray();
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#4 - Consistency

Every line of code adds a small amount of visual noise. The more code there is, the harder it is to read. That's why it's important to have rules. Keeping things like this consistent will help you recognize codes and patterns. This will result in less noise and more readable code.

Example#1

Before

class UserController 
{
    // ❌ 确定如何命名变量(驼峰或是蛇形等),不要混用!
    public function find($userId)
    {
    }
}
// ❌ 选择使用单数或者复数形式命名控制器,并保持一致
class InvoicesController 
{
    // ❌ 修改了样式,如花扣号的位置,影响可读性
    public function find($user_id) {
    }
}
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After

class UserController 
{
    // ✅ 所有变量驼峰式命名
    public function find($userId)
    {
    }
}
// ✅ 控制器命名规则一致(此处都使用单数)
class InvoiceController 
{
    // ✅ 花括号的位置(格式)一致,使代码更为可读
    public function find($userId)
    {
    }
}
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Example#2

Before

class PdfExporter
{
    // ❌ "handle" 和 "export" 是类似方法的不同名称
    public function handle(Collection $items): void
    {
        // export items...
    }
}
class CsvExporter
{
    public function export(Collection $items): void
    {
        // export items...
    }
}
// ❌ 使用时你会疑惑它们是否处理相似的任务
// ❌ 你可能需要再去查看类源码进行确定
$pdfExport->handle();
$csvExporter->export();
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After

// ✅ 可通过接口提供通用规则保持一致性
interface Exporter
{
    public function export(Collection $items): void;
}
class PdfExporter implements Exporter
{
    public function export(Collection $items): void
    {
        // export items...
    }
}
class CsvExporter implements Exporter
{
    public function export(Collection $items): void
    {
        // export items...
    }
}
// ✅ 对类似的任务使用相同的方法名,更具可读性
// ✅ 不用再去查看类源码,变可知它们都用在导出数据
$pdfExport->export();
$csvExporter->export();
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Refactoring❤️ Testing

I have already mentioned that refactoring does not change the functionality of the code. This is convenient when running tests, as they should also work after refactoring. That's why I only start refactoring code when I have tests. They will ensure that I don't inadvertently change the behavior of the code. So don’t forget to write tests and even go for TDD.

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source:learnku.com
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