Try Rector Online | Rector - Automated Way to Instantly Upgrade and Refactor any PHP code

Run Rector on your code to see what it can do for you:

 $initials = implode(
     '',
     array_map(
-        static fn ($name): string => strtoupper((string) $name[0]),
+        static fn (array $name): string => strtoupper((string) $name[0]),
         explode('.', $username),
     ),
 );

PHP snippet to change

<?php
$username = 'john.doe';

$initials = implode(
    '',
    array_map(
        static fn ($name): string => strtoupper((string) $name[0]),
        explode('.', $username),
    ),
);

Applied Rules:

AddArrowFunctionParamArrayWhereDimFetchRector

Not a change you expect?

Create an issue on GitHub
...or to speed up fix – add a test fixture

Config rector.php

<?php

use Rector\Config\RectorConfig;
use Rector\TypeDeclaration\Rector\Property\TypedPropertyFromAssignsRector;
use Rector\ValueObject\PhpVersion;

return RectorConfig::configure()
    // A. whole set
    ->withPreparedSets(typeDeclarations: true)
    // B. or few rules
    ->withRules([
        TypedPropertyFromAssignsRector::class
    ])
    // demonstrate specific PHP version
    ->withPhpVersion(PhpVersion::PHP_84);

Rector version: 142f1c - released at 2026-02-06 17:31