Add PhoneNumber::getGeographicalAreaCode()

src/PhoneNumber.php

@@ -81,6 +81,31 @@ public function getCountryCode() : string
         return (string) $this->phoneNumber->getCountryCode();
     }
 
+    /**
+     * Returns the geographical area code of this PhoneNumber.
+     *
+     * Notes:
+     *
+     *  - geographical area codes change over time, and this method honors those changes; therefore, it doesn't
+     *    guarantee the stability of the result it produces;
+     *  - most non-geographical numbers have no area codes, including numbers from non-geographical entities;
+     *  - some geographical numbers have no area codes.
+     *
+     * If this number has no area code, an empty string is returned.
+     *
+     * @return string
+     */
+    public function getGeographicalAreaCode() : string
+    {
+        $phoneNumberUtil = PhoneNumberUtil::getInstance();
+
+        $nationalSignificantNumber = $phoneNumberUtil->getNationalSignificantNumber($this->phoneNumber);
+
+        $areaCodeLength = $phoneNumberUtil->getLengthOfGeographicalAreaCode($this->phoneNumber);
+
+        return substr($nationalSignificantNumber, 0, $areaCodeLength);
+    }
+
     /**
      * Returns the national number of this PhoneNumber.
      *

tests/PhoneNumberTest.php

@@ -542,4 +542,26 @@ public function providerFormatForCallingFrom() : array
             ['+16502530000', 'GB', '00 1 650-253-0000'],
         ];
     }
+
+    /**
+     * @dataProvider providerGetGeographicalAreaCode
+     */
+    public function testGetGeographicalAreaCode(string $phoneNumber, string $areaCode) : void
+    {
+        $this->assertSame($areaCode, PhoneNumber::parse($phoneNumber)->getGeographicalAreaCode());
+    }
+
+    public function providerGetGeographicalAreaCode() : array
+    {
+        return [
+            ['+442079460585', '20'],
+            ['+441132224444', '113'],
+            ['+447553840000', ''],
+            ['+33123000000', '1'],
+            ['+33234000000', '2'],
+            ['+33345000000', '3'],
+            ['+33456000000', '4'],
+            ['+33567000000', '5'],
+        ];
+    }
 }