Add Collector class

Author: samsonasik

src/Collector.php

@@ -0,0 +1,98 @@
+<?php
+
+declare(strict_types=1);
+
+namespace ArrayLookup;
+
+use Traversable;
+use Webmozart\Assert\Assert;
+
+final class Collector
+{
+    /**
+     * @var array<int|string, mixed>|Traversable<int|string, mixed>
+     */
+    private static iterable $data = [];
+
+    /**
+     * @var callable(mixed $datum, int|string|null $key=): bool|null
+     */
+    private $when;
+
+    /**
+     * @var callable(mixed $datum, int|string|null $key=): mixed
+     */
+    private $transform;
+
+    private ?int $limit = null;
+
+    /**
+     * @param array<int|string, mixed>|Traversable<int|string, mixed> $data
+     */
+    public static function setUp(iterable $data): self
+    {
+        $self = new self();
+        $self->$data = $data;
+
+        return $self;
+    }
+
+    /**
+     * @param callable(mixed $datum, int|string|null $key=): bool $filter
+     */
+    public function when(callable $filter): self
+    {
+        $this->when = $filter;
+        return $this;
+    }
+
+    public function withLimit(int $limit): self
+    {
+        Assert::positiveInteger($limit);
+        $this->limit = $limit;
+
+        return $this;
+    }
+
+    /**
+     * @param callable(mixed $datum, int|string|null $key=): mixed $transform
+     */
+    public function withTransform(callable $transform): self
+    {
+        $this->transform = $transform;
+        return $this;
+    }
+
+    /**
+     * @return mixed[]
+     */
+    public function getResults(): array
+    {
+        // ensure when property is set early via ->when() and ->withTransform() method
+        Assert::isCallable($this->when);
+        Assert::isCallable($this->transform);
+
+        $count = 0;
+        $collectedData = [];
+
+        foreach ($this->data as $key => $datum) {
+            $isFound = ($this->when)($datum, $key);
+
+            Assert::boolean($isFound);
+
+            if (! $isFound) {
+                continue;
+            }
+
+            $collectedData[] = ($this->transform)($datum, $key);
+
+            ++$count;
+
+            if ($this->limit === $count) {
+                break;
+            }
+        }
+
+        return $collectedData;
+    }
+}