Add mapSubfields helper method on Field

Author: danmichaelo

src/Fields/Field.php

@@ -53,6 +53,11 @@ public function __get($key)
         }
     }
 
+    public function __toString()
+    {
+        return $this->field->__toString();
+    }
+
     /**
      * @param string|string[] $codes
      * @return array
@@ -93,6 +98,10 @@ protected function toString($codes, $glue = ' ')
      */
     public function sf($code, $default = null)
     {
+
+        // In PHP, ("a" == 0) will evaluate to TRUE, so it's actually very important that we ensure type here!
+        $code = (string) $code;
+
         $subfield = $this->getSubfield($code);
         if (!$subfield) {
             return $default;
@@ -101,6 +110,25 @@ public function sf($code, $default = null)
         return trim($subfield->getData());
     }
 
+    public function mapSubFields($map, $includeNullValues = false)
+    {
+        $o = [];
+        foreach ($map as $code => $prop) {
+            $value = $this->sf($code);
+
+            foreach ($this->getSubfields() as $q) {
+                if ($q->getCode() == $code) {
+                    $value = $q->getData();
+                }
+            }
+
+            if (!is_null($value) || $includeNullValues) {
+                $o[$prop] = $value;
+            }
+        }
+        return $o;
+    }
+
     public static function makeFieldObject(Record $record, $tag, $pcre=false)
     {
         $field = $record->getField($tag, $pcre);

tests/FieldsTest.php

@@ -27,6 +27,27 @@ public function testIsbn()
         );
     }
 
+    public function testMapSubfields()
+    {
+        $record = Record::fromString('<?xml version="1.0" encoding="UTF-8" ?>
+          <record xmlns="http://www.loc.gov/MARC21/slim">
+            <leader>99999cam a2299999 u 4500</leader>
+            <datafield tag="700" ind1="1" ind2=" ">
+              <subfield code="a">Levy, Silvio</subfield>
+              <subfield code="0">(NO-TrBIB)x90579165</subfield>
+            </datafield>
+          </record>');
+
+        $this->assertEquals([
+            'name' => 'Levy, Silvio',
+            'identifier' => '(NO-TrBIB)x90579165',
+        ], $record->getField('700')->mapSubfields([
+            'a' => 'name',
+            'b' => 'numeration',
+            '0' => 'identifier',
+        ]));
+    }
+
     public function test020withoutA()
     {
         $source = '<?xml version="1.0" encoding="UTF-8" ?>