Add function to return multiple rows in map for withMapping

src/Services/Writer.php

@@ -92,10 +92,16 @@ protected function iterateRows(object   $exportable,
 
         foreach ($rows as $index => $row) {
             $mappedRow = $withMapping ? $exportable->map($row) : $row;
-            $normalizedRow = $this->normalizeRow($mappedRow);
-            $formattedRow = $this->applyFormatting($normalizedRow, $formats, $index);
 
-            $this->writeRow($formattedRow);
+            $firstElement = is_array($mappedRow) ? reset($mappedRow) : null;
+
+            if ($withMapping && is_array($firstElement)) {
+                foreach ($mappedRow as $subRow) {
+                    $this->processAndWriteRow($subRow, $formats, $index);
+                }
+            } else {
+                $this->processAndWriteRow($mappedRow, $formats, $index);
+            }
         }
     }
 
@@ -178,6 +184,20 @@ protected function formatCellValue(mixed $value,
         return $value;
     }
 
+    /**
+     * @param mixed $row
+     * @param array $formats
+     * @param int $rowIndex
+     * @return void
+     * @throws InvalidCellValueException
+     */
+    protected function processAndWriteRow(mixed $row, array $formats, int $rowIndex): void
+    {
+        $normalizedRow = $this->normalizeRow($row);
+        $formattedRow = $this->applyFormatting($normalizedRow, $formats, $rowIndex);
+        $this->writeRow($formattedRow);
+    }
+
     /**
      * @param array $content
      * @return void

tests/Concerns/WithMappingTest.php

@@ -4,6 +4,7 @@
 
 use Vitorccs\LaravelCsv\Tests\Data\Database\Seeders\TestCsvSeeder;
 use Vitorccs\LaravelCsv\Tests\Data\Exports\WithMappingExport;
+use Vitorccs\LaravelCsv\Tests\Data\Exports\WithMappingMultipleRowsExport;
 use Vitorccs\LaravelCsv\Tests\Data\Imports\WithMappingImport;
 use Vitorccs\LaravelCsv\Tests\TestCase;
 
@@ -35,4 +36,14 @@ public function test_import_mapping()
 
         $this->assertSame($rows, $expected);
     }
+
+    public function test_export_mapping_multiple_rows()
+    {
+        $export = new WithMappingMultipleRowsExport();
+
+        $export->store($this->filename);
+        $actual = $this->getFromDisk($this->filename);
+
+        $this->assertSame($export->expected(), $actual);
+    }
 }

tests/Data/Exports/WithMappingMultipleRowsExport.php

@@ -0,0 +1,48 @@
+<?php
+
+namespace Vitorccs\LaravelCsv\Tests\Data\Exports;
+
+use Vitorccs\LaravelCsv\Concerns\Exportables\Exportable;
+use Vitorccs\LaravelCsv\Concerns\Exportables\FromQuery;
+use Vitorccs\LaravelCsv\Concerns\WithMapping;
+use Vitorccs\LaravelCsv\Tests\Data\Stubs\TestCsv;
+
+class WithMappingMultipleRowsExport implements FromQuery, WithMapping
+{
+	use Exportable;
+
+	public function query()
+	{
+		return TestCsv::query();
+	}
+
+	public function map($row): array
+	{
+		return [
+			[
+				$row->id,
+				$row->string . '_first',
+			],
+			[
+				$row->id,
+				$row->string . '_second',
+			],
+		];
+	}
+
+	public function expected(): string
+	{
+		return '1,text_1_first' . "\n" .
+			'1,text_1_second' . "\n" .
+			'2,text_2_first' . "\n" .
+			'2,text_2_second' . "\n" .
+			'3,text_3_first' . "\n" .
+			'3,text_3_second' . "\n" .
+			'4,text_4_first' . "\n" .
+			'4,text_4_second' . "\n" .
+			'5,text_5_first' . "\n" .
+			'5,text_5_second' . "\n" .
+			'6,text_6_first' . "\n" .
+			'6,text_6_second';
+	}
+}