diff --git a/docs/pages/code/gamma.php b/docs/pages/code/gamma.php
index 29a35c210..20d058ed5 100644
--- a/docs/pages/code/gamma.php
+++ b/docs/pages/code/gamma.php
@@ -6,9 +6,7 @@
 
 use loophp\collection\Collection;
 
-$addition = static function (float $value1, float $value2): float {
-    return $value1 + $value2;
-};
+$addition = static fn (float $value1, float $value2): float => $value1 + $value2;
 
 $listInt = static function (int $init, callable $succ): Generator {
     yield $init;
@@ -18,19 +16,11 @@
     }
 };
 
-$N = $listInt(1, static function (int $n): int {
-    return $n + 1;
-});
+$N = $listInt(1, static fn (int $n): int => $n + 1);
 
-$Y = static function (float $n): Closure {
-    return static function (int $x) use ($n): float {
-        return ($x ** ($n - 1)) * (\M_E ** (-$x));
-    };
-};
+$Y = static fn (float $n): Closure => static fn (int $x): float => ($x ** ($n - 1)) * (\M_E ** (-$x));
 
-$e = static function (float $value): bool {
-    return 10 ** -12 > $value;
-};
+$e = static fn (float $value): bool => 10 ** -12 > $value;
 
 // Find the factorial of this number. This is not bounded to integers!
 // $number = 3; // 2 * 2 => 4
diff --git a/docs/pages/code/monte-carlo.php b/docs/pages/code/monte-carlo.php
index 8750b3538..d38bea691 100644
--- a/docs/pages/code/monte-carlo.php
+++ b/docs/pages/code/monte-carlo.php
@@ -7,8 +7,8 @@
 use loophp\collection\Collection;
 
 $monteCarloMethod = static function ($in = 0, $total = 1): array {
-    $randomNumber1 = mt_rand(0, mt_getrandmax() - 1) / mt_getrandmax();
-    $randomNumber2 = mt_rand(0, mt_getrandmax() - 1) / mt_getrandmax();
+    $randomNumber1 = random_int(0, mt_getrandmax() - 1) / mt_getrandmax();
+    $randomNumber2 = random_int(0, mt_getrandmax() - 1) / mt_getrandmax();
 
     if (1 >= (($randomNumber1 ** 2) + ($randomNumber2 ** 2))) {
         ++$in;
diff --git a/docs/pages/code/operations/associate.php b/docs/pages/code/operations/associate.php
index d01a67f40..e0436aaaf 100644
--- a/docs/pages/code/operations/associate.php
+++ b/docs/pages/code/operations/associate.php
@@ -13,12 +13,8 @@
 
 Collection::fromIterable($input)
     ->associate(
-        static function ($key, $value) {
-            return $key * 2;
-        },
-        static function ($value, $key) {
-            return $value * 3;
-        }
+        static fn ($key, $value) => $key * 2,
+        static fn ($value, $key) => $value * 3
     );
 
 // [
@@ -34,9 +30,7 @@ static function ($value, $key) {
 
 Collection::fromIterable($input)
     ->associate(
-        static function ($key, $value) {
-            return $key * 2;
-        }
+        static fn ($key, $value) => $key * 2
     );
 
 // [
@@ -53,9 +47,7 @@ static function ($key, $value) {
 Collection::fromIterable($input)
     ->associate(
         null,
-        static function ($value, $key) {
-            return $value * 3;
-        }
+        static fn ($value, $key) => $value * 3
     );
 
 // [
diff --git a/docs/pages/code/operations/distinct.php b/docs/pages/code/operations/distinct.php
index c9b82ff5a..d20b83cd7 100644
--- a/docs/pages/code/operations/distinct.php
+++ b/docs/pages/code/operations/distinct.php
@@ -16,11 +16,8 @@
 // Example 2 -> Using a custom comparator callback, with object values
 final class User
 {
-    private string $name;
-
-    public function __construct(string $name)
+    public function __construct(private string $name)
     {
-        $this->name = $name;
     }
 
     public function name(): string
@@ -44,11 +41,8 @@ public function name(): string
 // Example 3 -> Using a custom accessor callback, with object values
 final class Person
 {
-    private string $name;
-
-    public function __construct(string $name)
+    public function __construct(private string $name)
     {
-        $this->name = $name;
     }
 
     public function name(): string
@@ -73,11 +67,8 @@ public function name(): string
 // Example 4 -> Using both accessor and comparator callbacks, with object values
 final class Cat
 {
-    private string $name;
-
-    public function __construct(string $name)
+    public function __construct(private string $name)
     {
-        $this->name = $name;
     }
 
     public function name(): string
diff --git a/docs/pages/code/operations/duplicate.php b/docs/pages/code/operations/duplicate.php
index 0aa0d33cf..c7e23ac7b 100644
--- a/docs/pages/code/operations/duplicate.php
+++ b/docs/pages/code/operations/duplicate.php
@@ -16,11 +16,8 @@
 // Example 2 -> Using a custom comparator callback, with object values
 final class User
 {
-    private string $name;
-
-    public function __construct(string $name)
+    public function __construct(private string $name)
     {
-        $this->name = $name;
     }
 
     public function name(): string
@@ -44,11 +41,8 @@ public function name(): string
 // Example 3 -> Using a custom accessor callback, with object values
 final class Person
 {
-    private string $name;
-
-    public function __construct(string $name)
+    public function __construct(private string $name)
     {
-        $this->name = $name;
     }
 
     public function name(): string
@@ -73,11 +67,8 @@ public function name(): string
 // Example 4 -> Using both accessor and comparator callbacks, with object values
 final class Cat
 {
-    private string $name;
-
-    public function __construct(string $name)
+    public function __construct(private string $name)
     {
-        $this->name = $name;
     }
 
     public function name(): string
diff --git a/docs/pages/code/operations/since.php b/docs/pages/code/operations/since.php
index 15e51ee93..6eadd4403 100644
--- a/docs/pages/code/operations/since.php
+++ b/docs/pages/code/operations/since.php
@@ -18,15 +18,15 @@
     // Implode characters to create a line string
     ->map(static fn (array $characters): string => implode('', $characters))
     // Skip items until the string "require-dev" is found.
-    ->since(static fn ($line): bool => false !== strpos($line, 'require-dev'))
+    ->since(static fn ($line): bool => str_contains($line, 'require-dev'))
     // Skip items after the string "}" is found.
-    ->until(static fn ($line): bool => false !== strpos($line, '}'))
+    ->until(static fn ($line): bool => str_contains($line, '}'))
     // Re-index the keys
     ->normalize()
     // Filter out the first line and the last line.
     ->filter(
         static fn ($line, $index): bool => 0 !== $index,
-        static fn ($line): bool => false === strpos($line, '}')
+        static fn ($line): bool => !str_contains($line, '}')
     )
     // Trim remaining results and explode the string on ':'.
     ->map(
diff --git a/docs/pages/code/operations/squash.php b/docs/pages/code/operations/squash.php
index 2ac274dcf..bfb8eab6a 100644
--- a/docs/pages/code/operations/squash.php
+++ b/docs/pages/code/operations/squash.php
@@ -26,7 +26,5 @@ static function (string $doc): string {
 // If no exception, you can continue the processing...
 $results = $results
     ->filter(
-        static function (string $document): bool {
-            return false !== strpos($document, 'foobar');
-        }
+        static fn (string $document): bool => str_contains($document, 'foobar')
     );
diff --git a/docs/pages/code/parse-git-log.php b/docs/pages/code/parse-git-log.php
index 2264d7114..a9a82349b 100644
--- a/docs/pages/code/parse-git-log.php
+++ b/docs/pages/code/parse-git-log.php
@@ -19,30 +19,24 @@
     fclose($fh);
 };
 
-$buildIfThenElseCallbacks = static function (string $lineStart): array {
-    return [
-        static function ($line) use ($lineStart): bool {
-            return is_string($line) && 0 === mb_strpos($line, $lineStart);
-        },
-        static function ($line) use ($lineStart): array {
-            [, $line] = explode($lineStart, $line);
+$buildIfThenElseCallbacks = static fn (string $lineStart): array => [
+    static fn ($line): bool => is_string($line) && 0 === mb_strpos($line, $lineStart),
+    static function ($line) use ($lineStart): array {
+        [, $line] = explode($lineStart, $line);
 
-            return [
-                sprintf(
-                    '%s:%s',
-                    mb_strtolower(str_replace(':', '', $lineStart)),
-                    trim($line)
-                ),
-            ];
-        },
-    ];
-};
+        return [
+            sprintf(
+                '%s:%s',
+                mb_strtolower(str_replace(':', '', $lineStart)),
+                trim($line)
+            ),
+        ];
+    },
+];
 
 $c = Collection::fromIterable($commandStream('git log'))
     ->map(
-        static function (string $value): string {
-            return trim($value);
-        }
+        static fn (string $value): string => trim($value)
     )
     ->compact('', ' ', "\n")
     ->ifThenElse(...$buildIfThenElseCallbacks('commit'))
@@ -52,73 +46,55 @@ static function (string $value): string {
     ->ifThenElse(...$buildIfThenElseCallbacks('Signed-off-by:'))
     ->split(
         Splitable::BEFORE,
-        static function ($value): bool {
-            return is_array($value) ?
-                (1 === preg_match('/^commit:\b[0-9a-f]{5,40}\b/', $value[0])) :
-                false;
-        }
+        static fn ($value): bool => is_array($value) ?
+            (1 === preg_match('/^commit:\b[0-9a-f]{5,40}\b/', $value[0])) :
+            false
     )
     ->map(
-        static function (array $value): CollectionInterface {
-            return Collection::fromIterable($value);
-        }
+        static fn (array $value): CollectionInterface => Collection::fromIterable($value)
     )
     ->map(
-        static function (CollectionInterface $collection): CollectionInterface {
-            return $collection
-                ->groupBy(
-                    static function ($value): ?string {
-                        return is_array($value) ? 'headers' : null;
-                    }
-                )
-                ->groupBy(
-                    static function ($value): ?string {
-                        return is_string($value) ? 'log' : null;
-                    }
-                )
-                ->ifThenElse(
-                    static function ($value, $key): bool {
-                        return 'headers' === $key;
-                    },
-                    static function ($value, $key): array {
-                        return Collection::fromIterable($value)
-                            ->unwrap()
-                            ->associate(
-                                static function ($carry, $key, string $value): string {
-                                    [$key, $line] = explode(':', $value, 2);
+        static fn (CollectionInterface $collection): CollectionInterface => $collection
+            ->groupBy(
+                static fn ($value): ?string => is_array($value) ? 'headers' : null
+            )
+            ->groupBy(
+                static fn ($value): ?string => is_string($value) ? 'log' : null
+            )
+            ->ifThenElse(
+                static fn ($value, $key): bool => 'headers' === $key,
+                static fn ($value, $key): array => Collection::fromIterable($value)
+                    ->unwrap()
+                    ->associate(
+                        static function ($carry, $key, string $value): string {
+                            [$key, $line] = explode(':', $value, 2);
 
-                                    return $key;
-                                },
-                                static function ($carry, $key, string $value): string {
-                                    [$key, $line] = explode(':', $value, 2);
+                            return $key;
+                        },
+                        static function ($carry, $key, string $value): string {
+                            [$key, $line] = explode(':', $value, 2);
 
-                                    return trim($line);
-                                }
-                            )
-                            ->all();
-                    }
-                );
-        }
+                            return trim($line);
+                        }
+                    )
+                    ->all()
+            )
     )
     ->map(
-        static function (CollectionInterface $collection): CollectionInterface {
-            return $collection
-                ->flatten()
-                ->groupBy(
-                    static function ($value, $key): ?string {
-                        if (is_numeric($key)) {
-                            return 'log';
-                        }
-
-                        return null;
+        static fn (CollectionInterface $collection): CollectionInterface => $collection
+            ->flatten()
+            ->groupBy(
+                static function ($value, $key): ?string {
+                    if (is_numeric($key)) {
+                        return 'log';
                     }
-                );
-        }
+
+                    return null;
+                }
+            )
     )
     ->map(
-        static function (CollectionInterface $collection): array {
-            return $collection->all();
-        }
+        static fn (CollectionInterface $collection): array => $collection->all()
     )
     ->limit(100);
 
diff --git a/docs/pages/code/primes.php b/docs/pages/code/primes.php
index 4a3455e95..1fc098ef4 100644
--- a/docs/pages/code/primes.php
+++ b/docs/pages/code/primes.php
@@ -11,9 +11,7 @@
 
     $iterator = new \CallbackFilterIterator(
         $iterator,
-        static function (int $a) use ($primeNumber): bool {
-            return 0 !== $a % $primeNumber;
-        }
+        static fn (int $a): bool => 0 !== $a % $primeNumber
     );
 
     $iterator->next();
@@ -29,14 +27,12 @@ static function (int $a) use ($primeNumber): bool {
     return yield from $integerGenerator($succ($init), $succ);
 };
 
-$limit = 1000000;
+$limit = 1_000_000;
 
 $primes = $primesGenerator(
     $integerGenerator(
         2,
-        static function (int $n): int {
-            return $n + 1;
-        }
+        static fn (int $n): int => $n + 1
     )
 );
 
@@ -45,9 +41,7 @@ static function (int $n): int {
     $primesGenerator(
         $integerGenerator(
             2,
-            static function (int $n): int {
-                return $n + 1;
-            }
+            static fn (int $n): int => $n + 1
         )
     )
 );
@@ -62,9 +56,7 @@ static function (int $n): int {
     $primesGenerator(
         $integerGenerator(
             2,
-            static function (int $n): int {
-                return $n + 1;
-            }
+            static fn (int $n): int => $n + 1
         )
     )
 );
@@ -73,9 +65,7 @@ static function (int $n): int {
 $lazyTwinPrimeNumbersCollection = Collection::fromIterable($lazyPrimeNumbersCollection)
     ->zip($lazyPrimeNumbersCollection->tail())
     ->filter(
-        static function (array $chunk): bool {
-            return 2 === $chunk[1] - $chunk[0];
-        }
+        static fn (array $chunk): bool => 2 === $chunk[1] - $chunk[0]
     );
 
 foreach ($lazyTwinPrimeNumbersCollection->limit($limit) as $prime) {
diff --git a/docs/pages/code/random-generator.php b/docs/pages/code/random-generator.php
index 815e2a2cc..4f0f5f6a3 100644
--- a/docs/pages/code/random-generator.php
+++ b/docs/pages/code/random-generator.php
@@ -7,7 +7,7 @@
 use loophp\collection\Collection;
 
 // Generate 300 distinct random numbers between 0 and 1000
-$random = static fn (): array => [mt_rand() / mt_getrandmax()];
+$random = static fn (): array => [random_int(0, mt_getrandmax()) / mt_getrandmax()];
 
 $random_numbers = Collection::unfold($random)
     ->unwrap()
diff --git a/docs/pages/code/random-numbers-distribution.php b/docs/pages/code/random-numbers-distribution.php
index 356370e61..384e2b686 100644
--- a/docs/pages/code/random-numbers-distribution.php
+++ b/docs/pages/code/random-numbers-distribution.php
@@ -28,14 +28,10 @@ static function (int $value) use ($max, $groups): string {
         }
     )
     ->groupBy(
-        static function ($value, $key) {
-            return $value;
-        }
+        static fn ($value, $key) => $value
     )
     ->map(
-        static function (array $value): int {
-            return count($value);
-        }
+        static fn (array $value): int => count($value)
     )
     ->sort(
         Sortable::BY_KEYS,
diff --git a/docs/pages/code/serialization.php b/docs/pages/code/serialization.php
index e8aef123c..157da5995 100644
--- a/docs/pages/code/serialization.php
+++ b/docs/pages/code/serialization.php
@@ -9,30 +9,30 @@
 // Example 1 -> using `json_encode`
 
 // a) with list, ordered keys
-json_encode(Collection::fromIterable([1, 2, 3])); // JSON: '[1, 2, 3]'
+json_encode(Collection::fromIterable([1, 2, 3]), \JSON_THROW_ON_ERROR); // JSON: '[1, 2, 3]'
 
 // b) with list, missing keys
 $col = Collection::fromIterable([1, 2, 3])
     ->filter(static fn (int $val): bool => $val % 2 !== 0); // [0 => 1, 2 => 3]
 
-json_encode($col); // JSON: '{"0": 1, "2": 3}'
+json_encode($col, \JSON_THROW_ON_ERROR); // JSON: '{"0": 1, "2": 3}'
 
 // c) with list, missing keys, with `normalize`
 $col = Collection::fromIterable([1, 2, 3])
     ->filter(static fn (int $val): bool => $val % 2 !== 0)
     ->normalize(); // [0 => 1, 1 => 3]
 
-json_encode($col); // JSON: '[1, 3]'
+json_encode($col, \JSON_THROW_ON_ERROR); // JSON: '[1, 3]'
 
 // d) with associative array
-json_encode(Collection::fromIterable(['foo' => 1, 'bar' => 2])); // JSON: '{"foo": 1, "bar": 2}'
+json_encode(Collection::fromIterable(['foo' => 1, 'bar' => 2]), \JSON_THROW_ON_ERROR); // JSON: '{"foo": 1, "bar": 2}'
 
 // e) with associative array, with `normalize`
 
 $col = Collection::fromIterable(['foo' => 1, 'bar' => 2])
     ->normalize(); // [0 => 1, 1 => 2]
 
-json_encode($col); // JSON: '[1, 2]'
+json_encode($col, \JSON_THROW_ON_ERROR); // JSON: '[1, 2]'
 
 // Example 2 -> using custom serializer (all previous behaviours apply)
 
diff --git a/docs/pages/code/simple.php b/docs/pages/code/simple.php
index 6f00fe20b..1f877d5e0 100644
--- a/docs/pages/code/simple.php
+++ b/docs/pages/code/simple.php
@@ -40,9 +40,7 @@
 // Map data
 $collection
     ->map(
-        static function ($value, $key): string {
-            return sprintf('%s.%s', $value, $value);
-        }
+        static fn ($value, $key): string => sprintf('%s.%s', $value, $value)
     )
     ->all(); // ['A.A', 'B.B', 'C.C', 'D.D', 'E.E']
 
@@ -104,7 +102,7 @@ static function ($value, $key): bool {
     );
 
 // Generate 300 distinct random numbers between 0 and 1000
-$random = static fn (): array => [mt_rand() / mt_getrandmax()];
+$random = static fn (): array => [random_int(0, mt_getrandmax()) / mt_getrandmax()];
 
 Collection::unfold($random)
     ->unwrap()
@@ -146,15 +144,11 @@ static function ($value, $key): bool {
 Collection::fromIterable($readFileLineByLine($hugeFile))
     // Add the line number at the end of the line, as comment.
     ->map(
-        static function ($value, $key): string {
-            return str_replace(\PHP_EOL, ' // line ' . $key . \PHP_EOL, $value);
-        }
+        static fn ($value, $key): string => str_replace(\PHP_EOL, ' // line ' . $key . \PHP_EOL, $value)
     )
     // Find public static fields or methods among the results.
     ->filter(
-        static function ($value, $key): bool {
-            return false !== mb_strpos(trim($value), 'public static');
-        }
+        static fn ($value, $key): bool => false !== mb_strpos(trim($value), 'public static')
     )
     // Drop the first result.
     ->drop(1)