Add support min and minBy to collections

Author: decole

src/Fp/Collections/ArrayList.php

@@ -30,6 +30,8 @@
 use Fp\Operations\MapValuesOperation;
 use Fp\Operations\MaxByElementOperation;
 use Fp\Operations\MaxElementOperation;
+use Fp\Operations\MinByElementOperation;
+use Fp\Operations\MinElementOperation;
 use Fp\Operations\MkStringOperation;
 use Fp\Operations\PrependedAllOperation;
 use Fp\Operations\PrependedOperation;
@@ -627,4 +629,23 @@ public function maxBy(callable $callback): Option
     {
         return MaxByElementOperation::of($this->getIterator())($callback);
     }
+
+    /**
+     * @inheritDoc
+     * @return Option<TV>
+     */
+    public function min(): Option
+    {
+        return MinElementOperation::of($this->getIterator())();
+    }
+
+    /**
+     * @inheritDoc
+     * @psalm-param callable(TV): mixed $callback
+     * @return Option<TV>
+     */
+    public function minBy(callable $callback): Option
+    {
+        return MinByElementOperation::of($this->getIterator())($callback);
+    }
 }

src/Fp/Collections/LinkedList.php

@@ -31,6 +31,8 @@
 use Fp\Operations\MapValuesOperation;
 use Fp\Operations\MaxByElementOperation;
 use Fp\Operations\MaxElementOperation;
+use Fp\Operations\MinByElementOperation;
+use Fp\Operations\MinElementOperation;
 use Fp\Operations\MkStringOperation;
 use Fp\Operations\PrependedAllOperation;
 use Fp\Operations\ReduceOperation;
@@ -639,4 +641,23 @@ public function maxBy(callable $callback): Option
     {
         return MaxByElementOperation::of($this->getIterator())($callback);
     }
+
+    /**
+     * @inheritDoc
+     * @return Option<TV>
+     */
+    public function min(): Option
+    {
+        return MinElementOperation::of($this->getIterator())();
+    }
+
+    /**
+     * @inheritDoc
+     * @psalm-param callable(TV): mixed $callback
+     * @return Option<TV>
+     */
+    public function minBy(callable $callback): Option
+    {
+        return MinByElementOperation::of($this->getIterator())($callback);
+    }
 }

src/Fp/Collections/SeqTerminalOps.php

@@ -308,4 +308,29 @@ public function max(): Option;
      * @psalm-return Option<TV>
      */
     public function maxBy(callable $callback): Option;
+
+    /**
+     * Returns the minimum value from collection
+     *
+     * ```php
+     * >>> LinkedList::collect([1, 4, 2])->min()->get();
+     * => 1
+     * ```
+     *
+     * @psalm-return Option<TV>
+     */
+    public function min(): Option;
+
+    /**
+     * Returns the minimum value from collection by iterating each element using the callback
+     *
+     * ```php
+     * >>> LinkedList::collect([new Foo(1), new Bar(6), new Foo(2)])->minBy(fn(Foo $foo) => $foo->a)->get();
+     * => 1
+     * ```
+     *
+     * @psalm-param callable(TV): mixed $callback
+     * @psalm-return Option<TV>
+     */
+    public function minBy(callable $callback): Option;
 }

src/Fp/Operations/MaxByElementOperation.php

@@ -32,5 +32,4 @@ public function __invoke(callable $by): Option
 
         return FirstOperation::of($gen)();
     }
-
 }

src/Fp/Operations/MaxElementOperation.php

@@ -25,4 +25,4 @@ public function __invoke(): Option
 
         return Option::fromNullable(!empty($list) ? max($list) : null);
     }
-}
+}

src/Fp/Operations/MinByElementOperation.php

@@ -0,0 +1,35 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Fp\Operations;
+
+use Fp\Functional\Option\Option;
+
+/**
+ * @psalm-immutable
+ * @template TK
+ * @template TV
+ * @extends AbstractOperation<TK, TV>
+ */
+class MinByElementOperation extends AbstractOperation
+{
+    /**
+     * @psalm-param callable(TV): mixed $by
+     * @return Option<TV>
+     */
+    public function __invoke(callable $by): Option
+    {
+        $f =
+            /**
+             * @param TV $r
+             * @param TV $l
+             * @return int
+             */
+            fn(mixed $r, mixed $l): int => $by($l) <=> $by($r);
+
+        $gen = SortedOperation::of($this->gen)($f);
+
+        return LastOperation::of($gen)();
+    }
+}

src/Fp/Operations/MinElementOperation.php

@@ -0,0 +1,27 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Fp\Operations;
+
+use Fp\Functional\Option\Option;
+use function Fp\Cast\asList;
+
+/**
+ * @psalm-immutable
+ * @template TK
+ * @template TV
+ * @extends AbstractOperation<TK, TV>
+ */
+class MinElementOperation extends AbstractOperation
+{
+    /**
+     * @return Option<TV>
+     */
+    public function __invoke(): Option
+    {
+        $list = asList($this->gen);
+
+        return Option::fromNullable(!empty($list) ? min($list) : null);
+    }
+}

tests/Runtime/Interfaces/Seq/SeqOpsTest.php

@@ -657,4 +657,76 @@ public function testMaxByInEmptyCollection(Seq $seq, Option $option): void
     {
         $this->assertEquals($option, $seq->maxBy(fn(Foo $foo) => $foo->a));
     }
+
+    public function provideTestMinNotEmptyCollections(): Generator
+    {
+        yield ArrayList::class => [ArrayList::collect([3, 7, 2]), Option::some(2)];
+        yield LinkedList::class => [LinkedList::collect([9, 1, 2]), Option::some(1)];
+    }
+
+    /**
+     * @dataProvider provideTestMinNotEmptyCollections
+     */
+    public function testMinInNotEmptyCollection(Seq $seq, Option $option): void
+    {
+        $this->assertEquals($option, $seq->min());
+    }
+
+    public function provideTestMinEmptyCollections(): Generator
+    {
+        yield ArrayList::class => [ArrayList::collect([]), Option::none()];
+        yield LinkedList::class => [LinkedList::collect([]), Option::none()];
+    }
+
+    /**
+     * @dataProvider provideTestMinEmptyCollections
+     */
+    public function testMinInEmptyCollection(Seq $seq, Option $option): void
+    {
+        $this->assertEquals($option, $seq->min());
+    }
+
+    public function provideTestMinByNotEmptyCollections(): Generator
+    {
+        yield ArrayList::class => [
+            ArrayList::collect([new Foo(1), new Foo(5), new Foo(2)]),
+            Option::some(new Foo(1))
+        ];
+        yield LinkedList::class => [
+            LinkedList::collect([new Foo(9), new Foo(4), new Foo(2)]),
+            Option::some(new Foo(2))
+        ];
+    }
+
+    /**
+     * @param Seq<Foo> $seq
+     * @param Option<Foo> $option
+     * @dataProvider provideTestMinByNotEmptyCollections
+     */
+    public function testMinByInNotEmptyCollection(Seq $seq, Option $option): void
+    {
+        $this->assertEquals($option, $seq->minBy(fn(Foo $foo) => $foo->a));
+    }
+
+    public function provideTestMinByEmptyCollections(): Generator
+    {
+        yield ArrayList::class => [
+            ArrayList::collect([]),
+            Option::none()
+        ];
+        yield LinkedList::class => [
+            LinkedList::collect([]),
+            Option::none()
+        ];
+    }
+
+    /**
+     * @param Seq<Foo> $seq
+     * @param Option<Foo> $option
+     * @dataProvider provideTestMinByEmptyCollections
+     */
+    public function testMinByInEmptyCollection(Seq $seq, Option $option): void
+    {
+        $this->assertEquals($option, $seq->minBy(fn(Foo $foo) => $foo->a));
+    }
 }