Add map and reduce to Periodcollection

CHANGELOG.md

@@ -2,6 +2,10 @@
 
 All notable changes to `period` will be documented in this file
 
+## 1.4.0 - 2019-04-23
+
+- Add `map` and `reduce` to `PeriodCollection`
+
 ## 1.3.1 - 2019-04-19
 
 - Remove unused code

README.md

@@ -117,6 +117,8 @@ $period->diff(Period ...$periods): PeriodCollection
 ```php
 $periodCollection->overlap(PeriodCollection ...$periodCollections): PeriodCollection
 $periodCollection->overlapSingle(PeriodCollection $periodCollection): PeriodCollection
+$periodCollection->map(Closure<Period> $closure): PeriodCollection
+$periodCollection->reduce(Closure<mixed, Period> $closure): mixed
 ```
 
 ```php

src/PeriodCollection.php

@@ -2,6 +2,7 @@
 
 namespace Spatie\Period;
 
+use Closure;
 use Iterator;
 use Countable;
 use ArrayAccess;
@@ -119,6 +120,28 @@ public function add(Period ...$periods): PeriodCollection
         return $collection;
     }
 
+    public function map(Closure $closure): PeriodCollection
+    {
+        $collection = clone $this;
+
+        foreach ($collection->periods as $key => $period) {
+            $collection->periods[$key] = $closure($period);
+        }
+
+        return $collection;
+    }
+
+    public function reduce(Closure $closure, $initial = null)
+    {
+        $carry = $initial;
+
+        foreach ($this as $period) {
+            $carry = $closure($carry, $period);
+        }
+
+        return $carry;
+    }
+
     public function isEmpty(): bool
     {
         return count($this->periods) === 0;

tests/PeriodCollectionTest.php

@@ -173,4 +173,35 @@ public function intersect_test()
         $this->assertTrue($intersect[1]->equals(Period::make('2019-01-09', '2019-01-10')));
         $this->assertTrue($intersect[2]->equals(Period::make('2019-01-10', '2019-01-11')));
     }
+
+    /** @test */
+    public function map()
+    {
+        $collection = new PeriodCollection(
+            Period::make('2019-01-01', '2019-01-02'),
+            Period::make('2019-01-01', '2019-01-02'),
+        );
+
+        $mapped = $collection->map(function (Period $period) {
+            return $period;
+        });
+
+        $this->assertTrue($mapped[0]->equals($collection[0]));
+        $this->assertTrue($mapped[1]->equals($collection[1]));
+    }
+
+    /** @test */
+    public function reduce()
+    {
+        $collection = new PeriodCollection(
+            Period::make('2019-01-01', '2019-01-02'),
+            Period::make('2019-01-03', '2019-01-04'),
+        );
+
+        $totalLength = $collection->reduce(function (int $carry, Period $period) {
+            return $carry + $period->length();
+        }, 0);
+
+        $this->assertEquals(4, $totalLength);
+    }
 }