[Collection] Stream toAssocArray cast.

Author: whsv26

src/Fp/Streams/Stream.php

@@ -52,6 +52,7 @@
 use SplFileObject;
 
 use function Fp\Callable\asGenerator;
+use function Fp\Cast\asArray;
 use function Fp\Cast\asList;
 
 /**
@@ -622,6 +623,24 @@ public function toArray(): array
         return $this->leaf(asList($this->emitter));
     }
 
+    /**
+     * @inheritDoc
+     * @template TKO of array-key
+     * @template TVO
+     * @param callable(TV): array{TKO, TVO} $callback
+     * @return array<TKO, TVO>
+     */
+    public function toAssocArray(callable $callback): array
+    {
+        /** @psalm-suppress ImpureFunctionCall */
+        return $this->leaf(asArray(asGenerator(function () use ($callback) {
+            foreach ($this->emitter as $val) {
+                $pair = $callback($val);
+                yield $pair[0] => $pair[1];
+            }
+        })));
+    }
+
     /**
      * @inheritDoc
      * @return LinkedList<TV>

src/Fp/Streams/StreamCastableOps.php

@@ -27,6 +27,19 @@ interface StreamCastableOps
      */
     public function toArray(): array;
 
+    /**
+     * ```php
+     * >>> Stream::emits([[1, 'a'], [2, 'b']])->toAssocArray(fn($pair) => $pair);
+     * => [1 => 'a', 2 => 'b']
+     * ```
+     *
+     * @template TKO of array-key
+     * @template TVO
+     * @param callable(TV): array{TKO, TVO} $callback
+     * @return array<TKO, TVO>
+     */
+    public function toAssocArray(callable $callback): array;
+
     /**
      * ```php
      * >>> Stream::emits([1, 2, 2])->toLinkedList();

tests/Runtime/Classes/Stream/StreamTest.php

@@ -38,5 +38,10 @@ public function testCasts(): void
         $this->assertEquals([[0, 0], [1, 1]], Stream::emits([0, 1])->toHashMap(fn($e) => [$e, $e])->toArray());
         $this->assertInstanceOf(Some::class, Option::try(fn() => Stream::emits([0, 1])->toFile('/dev/null', false)));
         $this->assertInstanceOf(Some::class, Option::try(fn() => Stream::emits([0, 1])->toFile('/dev/null', true)));
+
+        $this->assertEquals(
+            [1 => 'a', 2 => 'b'],
+            Stream::emits([[1, 'a'], [2, 'b']])->toAssocArray(fn($pair) => $pair)
+        );
     }
 }