feat: Add Find operation (#204)

docs/pages/api.rst

@@ -813,6 +813,27 @@ Signature: ``Collection::filter(callable ...$callbacks): Collection;``
 .. literalinclude:: code/operations/filter.php
   :language: php
 
+find
+~~~~
+
+Find a collection item using one or more callbacks. If the value cannot be found, that is, no callback returns true for
+any collection item, it will return the ``$default`` value.
+
+.. warning:: The ``callbacks`` parameter is variadic and will be evaluated as a logical ``OR``.
+             If you're looking for a logical ``AND``, you have to make multiple calls to the
+             same operation.
+
+.. tip:: This operation is a shortcut for ``filter`` + ``current``.
+
+.. tip:: It is only when the callback returns ``true`` that the value is selected.
+
+Interface: `Findable`_
+
+Signature: ``Collection::find($default = null, callable ...$callbacks);``
+
+.. literalinclude:: code/operations/find.php
+  :language: php
+
 first
 ~~~~~
 
@@ -2509,6 +2530,7 @@ Signature: ``Collection::zip(iterable ...$iterables): Collection;``
 .. _Explodeable: https://github.com/loophp/collection/blob/master/src/Contract/Operation/Explodeable.php
 .. _Falsyable: https://github.com/loophp/collection/blob/master/src/Contract/Operation/Falsyable.php
 .. _Filterable: https://github.com/loophp/collection/blob/master/src/Contract/Operation/Filterable.php
+.. _Findable: https://github.com/loophp/collection/blob/master/src/Contract/Operation/Findable.php
 .. _Firstable: https://github.com/loophp/collection/blob/master/src/Contract/Operation/Firstable.php
 .. _FlatMapable: https://github.com/loophp/collection/blob/master/src/Contract/Operation/FlatMapable.php
 .. _Flattenable: https://github.com/loophp/collection/blob/master/src/Contract/Operation/Flattenable.php

docs/pages/code/operations/find.php

@@ -0,0 +1,47 @@
+<?php
+
+/**
+ * For the full copyright and license information, please view
+ * the LICENSE file that was distributed with this source code.
+ */
+
+declare(strict_types=1);
+
+namespace App;
+
+use loophp\collection\Collection;
+
+use function range;
+
+include __DIR__ . '/../../../../vendor/autoload.php';
+
+$divisibleBy3 = static fn ($value): bool => 0 === $value % 3;
+
+// Example 1: find a value and use the default `null` if not found
+$value = Collection::fromIterable(range(1, 10))
+    ->find(null, $divisibleBy3); // 3
+
+$value = Collection::fromIterable([1, 2, 4])
+    ->find(null, $divisibleBy3); // null
+
+$value = Collection::fromIterable(['foo' => 'f', 'bar' => 'b'])
+    ->find(null, static fn ($value): bool => 'b' === $value); // 'b'
+
+$value = Collection::fromIterable(['foo' => 'f', 'bar' => 'b'])
+    ->find(null, static fn ($value): bool => 'x' === $value); // null
+
+// Example 2: find a value and use a custom default if not found
+$value = Collection::fromIterable([1, 2, 4])
+    ->find(-1, $divisibleBy3); // -1
+
+$value = Collection::fromIterable(['foo' => 'f', 'bar' => 'b'])
+    ->find(404, static fn ($value): bool => 'x' === $value); // 404
+
+// Example 3: use with a Doctrine Query
+/** @var EntityManagerInterface $em */
+$q = $em->createQuery('SELECT u FROM MyProject\Model\Product p');
+
+$isBook = static fn ($product): bool => 'books' === $product->getCategory();
+
+$value = Collection::fromIterable($q->toIterable())
+    ->find(null, $isBook);

spec/loophp/collection/CollectionSpec.php

@@ -1401,6 +1401,29 @@ public function it_can_filter(): void
             ->shouldIterateAs([true]);
     }
 
+    public function it_can_find(): void
+    {
+        $this::fromIterable(['foo' => 'a', 'bar' => 'b'])
+            ->find('missing', static fn ($value): bool => 'b' === $value)
+            ->shouldReturn('b');
+
+        $this::fromIterable(['foo' => 'a', 'bar' => 'b'])
+            ->find('missing', static fn ($value): bool => 'd' === $value)
+            ->shouldReturn('missing');
+
+        $this::fromIterable([1, 3, 5])
+            ->find(null, static fn ($value): bool => $value % 2 === 0)
+            ->shouldBeNull();
+
+        $this::fromIterable([1, 3, 5])
+            ->find(-1, static fn ($value): bool => $value % 2 === 0)
+            ->shouldReturn(-1);
+
+        $this::fromIterable([1, 3, 5])
+            ->find(null, static fn ($value): bool => $value % 2 !== 0)
+            ->shouldReturn(1);
+    }
+
     public function it_can_flatMap(): void
     {
         $this::fromIterable([1, 2, 3])

src/Collection.php

@@ -49,6 +49,7 @@
 use loophp\collection\Operation\Explode;
 use loophp\collection\Operation\Falsy;
 use loophp\collection\Operation\Filter;
+use loophp\collection\Operation\Find;
 use loophp\collection\Operation\First;
 use loophp\collection\Operation\FlatMap;
 use loophp\collection\Operation\Flatten;
@@ -393,6 +394,11 @@ public function filter(callable ...$callbacks): CollectionInterface
         return new self(Filter::of()(...$callbacks), [$this->getIterator()]);
     }
 
+    public function find($default = null, callable ...$callbacks)
+    {
+        return (new self(Find::of()($default)(...$callbacks), [$this->getIterator()]))->getIterator()->current();
+    }
+
     public function first(): CollectionInterface
     {
         return new self(First::of(), [$this->getIterator()]);

src/Contract/Collection.php

@@ -42,6 +42,7 @@
 use loophp\collection\Contract\Operation\Explodeable;
 use loophp\collection\Contract\Operation\Falsyable;
 use loophp\collection\Contract\Operation\Filterable;
+use loophp\collection\Contract\Operation\Findable;
 use loophp\collection\Contract\Operation\Firstable;
 use loophp\collection\Contract\Operation\FlatMapable;
 use loophp\collection\Contract\Operation\Flattenable;
@@ -164,6 +165,7 @@
  * @template-extends Explodeable<TKey, T>
  * @template-extends Falsyable<TKey, T>
  * @template-extends Filterable<TKey, T>
+ * @template-extends Findable<TKey, T>
  * @template-extends Firstable<TKey, T>
  * @template-extends FlatMapable<TKey, T>
  * @template-extends Flattenable<TKey, T>
@@ -280,6 +282,7 @@ interface Collection extends
     Explodeable,
     Falsyable,
     Filterable,
+    Findable,
     Firstable,
     FlatMapable,
     Flattenable,

src/Contract/Operation/Findable.php

@@ -0,0 +1,34 @@
+<?php
+
+/**
+ * For the full copyright and license information, please view
+ * the LICENSE file that was distributed with this source code.
+ */
+
+declare(strict_types=1);
+
+namespace loophp\collection\Contract\Operation;
+
+use Iterator;
+
+/**
+ * @template T
+ * @template TKey
+ */
+interface Findable
+{
+    /**
+     * Find a value in the collection that matches all predicates or return the
+     * default value.
+     *
+     * @see https://loophp-collection.readthedocs.io/en/stable/pages/api.html#find
+     *
+     * @template V
+     *
+     * @param V $default
+     * @param (callable(T=, TKey=, Iterator<TKey, T>=): bool) ...$callbacks
+     *
+     * @return T|V
+     */
+    public function find($default = null, callable ...$callbacks);
+}

src/Operation/Find.php

@@ -0,0 +1,59 @@
+<?php
+
+/**
+ * For the full copyright and license information, please view
+ * the LICENSE file that was distributed with this source code.
+ */
+
+declare(strict_types=1);
+
+namespace loophp\collection\Operation;
+
+use Closure;
+use Generator;
+use Iterator;
+
+/**
+ * @immutable
+ *
+ * @template TKey
+ * @template T
+ *
+ * phpcs:disable Generic.Files.LineLength.TooLong
+ */
+final class Find extends AbstractOperation
+{
+    /**
+     * @pure
+     *
+     * @template V
+     *
+     * @return Closure(V): Closure(callable(T=, TKey=, Iterator<TKey, T>=): bool ...): Closure(Iterator<TKey, T>): Generator<TKey, T|V>
+     */
+    public function __invoke(): Closure
+    {
+        return
+            /**
+             * @param V $default
+             *
+             * @return Closure(callable(T=, TKey=, Iterator<TKey, T>=): bool ...): Closure(Iterator<TKey, T>): Generator<TKey, T|V>
+             */
+            static fn ($default): Closure =>
+                /**
+                 * @param callable(T=, TKey=, Iterator<TKey, T>=): bool ...$callbacks
+                 *
+                 * @return Closure(Iterator<TKey, T>): Generator<TKey, T|V>
+                 */
+                static function (callable ...$callbacks) use ($default): Closure {
+                    /** @var Closure(Iterator<TKey, T>): Generator<TKey, T|V> $pipe */
+                    $pipe = Pipe::of()(
+                        Filter::of()(...$callbacks),
+                        Append::of()($default),
+                        Head::of(),
+                    );
+
+                    // Point free style.
+                    return $pipe;
+                };
+    }
+}

tests/static-analysis/find.php

@@ -0,0 +1,77 @@
+<?php
+
+/**
+ * For the full copyright and license information, please view
+ * the LICENSE file that was distributed with this source code.
+ */
+
+declare(strict_types=1);
+
+include __DIR__ . '/../../vendor/autoload.php';
+
+use loophp\collection\Collection;
+
+function find_checkIntElement(int $value): void
+{
+}
+function find_checkNullableInt(?int $value): void
+{
+}
+function find_checkStringElement(string $value): void
+{
+}
+function find_checkNullableString(?string $value): void
+{
+}
+
+$intValueCallback = static fn (int $value): bool => $value % 2 === 0;
+$intValueCallback2 = static fn (int $value): bool => 2 < $value;
+$intKeyValueCallback1 = static fn (int $value, int $key): bool => $value % 2 === 0 && $key % 2 === 0;
+$intKeyValueCallback2 = static fn (int $value, int $key): bool => 2 < $value && 2 < $key;
+
+$stringValueCallback = static fn (string $value): bool => 'bar' === $value;
+$stringValueCallback2 = static fn (string $value): bool => '' === $value;
+$stringKeyValueCallback1 = static fn (string $value, string $key): bool => 'bar' !== $value && 'foo' !== $key;
+$stringKeyValueCallback2 = static fn (string $value, string $key): bool => 'bar' !== $value && '' === $key;
+
+find_checkNullableInt(Collection::fromIterable([1, 2, 3])->find(null, $intValueCallback));
+find_checkNullableInt(Collection::fromIterable([1, 2, 3])->find(null, $intValueCallback, $intValueCallback2));
+find_checkNullableInt(Collection::fromIterable([1, 2, 3])->find(null, $intKeyValueCallback1));
+find_checkNullableInt(Collection::fromIterable([1, 2, 3])->find(null, $intKeyValueCallback1, $intKeyValueCallback2));
+
+find_checkNullableString(Collection::fromIterable(['foo' => 'a', 'bar' => 'b'])->find(null, $stringValueCallback));
+find_checkNullableString(Collection::fromIterable(['foo' => 'a', 'bar' => 'b'])->find(null, $stringValueCallback, $stringValueCallback2));
+find_checkNullableString(Collection::fromIterable(['foo' => 'a', 'bar' => 'b'])->find(null, $stringKeyValueCallback1));
+find_checkNullableString(Collection::fromIterable(['foo' => 'a', 'bar' => 'b'])->find(null, $stringKeyValueCallback1, $stringKeyValueCallback2));
+
+find_checkIntElement(Collection::fromIterable([1, 2, 3])->find(-1, $intValueCallback));
+find_checkStringElement(Collection::fromIterable(['foo' => 'a', 'bar' => 'b'])->find('not found', $stringValueCallback));
+
+// VALID failures - `null` as default value
+/** @psalm-suppress PossiblyNullArgument @phpstan-ignore-next-line */
+find_checkIntElement(Collection::fromIterable([1, 2, 3])->find(null, $intValueCallback));
+/** @psalm-suppress PossiblyNullArgument @phpstan-ignore-next-line */
+find_checkStringElement(Collection::fromIterable(['foo' => 'a', 'bar' => 'b'])->find(null, $stringValueCallback));
+
+// VALID failures - default value type mismatch
+/** @psalm-suppress PossiblyInvalidArgument @phpstan-ignore-next-line */
+find_checkIntElement(Collection::fromIterable([1, 2, 3])->find('not integer', $intValueCallback));
+/** @psalm-suppress PossiblyInvalidArgument @phpstan-ignore-next-line */
+find_checkStringElement(Collection::fromIterable(['foo' => 'a', 'bar' => 'b'])->find(-1, $stringValueCallback));
+
+/*
+PHP 8 - using named parameters and the default `null` value -> these should work fine,
+but Psalm reports no issue and PHPStan is reporting an unexpected issue:
+"Parameter #1 $value of function find_checkNullableInt expects int|null, (Closure)|int given."
+
+find_checkNullableInt(Collection::fromIterable([1, 2, 3])->find(callbacks: $intValueCallback));
+find_checkNullableString(Collection::fromIterable(['foo' => 'a', 'bar' => 'b'])->find(callbacks: $stringValueCallback));
+ */
+
+/*
+PHP 8 - using named parameters and the default `null` value -> these should legitimately fail,
+but Psalm reports no issue and the current PHPStan failures are due to the error mentioned above.
+
+find_checkIntElement(Collection::fromIterable([1, 2, 3])->find(callbacks: $intValueCallback));
+find_checkStringElement(Collection::fromIterable(['foo' => 'a', 'bar' => 'b'])->find(callbacks: $stringValueCallback));
+ */