variables.md

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Variables

Use meaningful and pronounceable variable names

Bad:

$ymdstr = $moment->format('y-m-d');

Good:

$currentDate = $moment->format('y-m-d');

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Use the same vocabulary for the same type of variable

Bad:

getUserInfo();
getUserData();
getUserRecord();
getUserProfile();

Good:

getUser();

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Use searchable names (part 1)

We will read more code than we will ever write. It's important that the code we do write is readable and searchable. By not naming variables that end up being meaningful for understanding our program, we hurt our readers. Make your names searchable. Sample Link

Bad:

// What the heck is 448 for?
$result = $serializer->serialize($data, 448);

Good:

$json = $serializer->serialize($data, JSON_UNESCAPED_SLASHES | JSON_PRETTY_PRINT | JSON_UNESCAPED_UNICODE);

Use searchable names (part 2)

Bad:

class User
{
    // What the heck is 7 for?
    public $access = 7;
}

// What the heck is 4 for?
if ($user->access & 4) {
    // ...
}

Good:

class User
{
    public const ACCESS_READ = 1;

    public const ACCESS_CREATE = 2;

    public const ACCESS_UPDATE = 4;

    public const ACCESS_DELETE = 8;

    // User as default can read, create and update something
    public $access = self::ACCESS_READ | self::ACCESS_CREATE | self::ACCESS_UPDATE;
}

if ($user->access & User::ACCESS_UPDATE) {
    // do edit ...
}

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Avoid nesting too deeply and return early (part 1)

Too many if-else statements can make your code hard to follow. Explicit is better than implicit.

Bad:

function isShopOpen($day): bool
{
    if ($day) {
        if (is_string($day)) {
            $day = strtolower($day);
            if ($day === 'friday') {
                return true;
            } elseif ($day === 'saturday') {
                return true;
            } elseif ($day === 'sunday') {
                return true;
            }
            return false;
        }
        return false;
    }
    return false;
}

Good:

function isShopOpen(string $day): bool
{
    if (empty($day)) {
        return false;
    }

    $openingDays = ['friday', 'saturday', 'sunday'];

    return in_array(strtolower($day), $openingDays, true);
}

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Avoid nesting too deeply and return early (part 2)

Bad:

function fibonacci(int $n)
{
    if ($n < 50) {
        if ($n !== 0) {
            if ($n !== 1) {
                return fibonacci($n - 1) + fibonacci($n - 2);
            }
            return 1;
        }
        return 0;
    }
    return 'Not supported';
}

Good:

function fibonacci(int $n): int
{
    if ($n === 0 || $n === 1) {
        return $n;
    }

    if ($n >= 50) {
        throw new Exception('Not supported');
    }

    return fibonacci($n - 1) + fibonacci($n - 2);
}

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Avoid Mental Mapping

Don’t force the reader of your code to translate what the variable means. Explicit is better than implicit.

Bad:

$l = ['Austin', 'New York', 'San Francisco'];

for ($i = 0; $i < count($l); $i++) {
    $li = $l[$i];
    doStuff();
    doSomeOtherStuff();
    // ...
    // ...
    // ...
    // Wait, what is `$li` for again?
    dispatch($li);
}

Good:

$locations = ['Austin', 'New York', 'San Francisco'];

foreach ($locations as $location) {
    doStuff();
    doSomeOtherStuff();
    // ...
    // ...
    // ...
    dispatch($location);
}

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Don't add unneeded context

If your class/object name tells you something, don't repeat that in your variable name.

Bad:

class Car
{
    public $carMake;

    public $carModel;

    public $carColor;

    //...
}

Good:

class Car
{
    public $make;

    public $model;

    public $color;

    //...
}