Allow defaulting end parameter to start value in findBetween

framework/helpers/BaseStringHelper.php

@@ -529,17 +529,22 @@ public static function mask($string, $start, $length, $mask = '*') {
     }
 
     /**
-     * Returns the portion of the string that lies between the first occurrence of the start string
-     * and the last occurrence of the end string after that.
+     * Returns the portion of the string that lies between the first occurrence of the `$start` string
+     * and the last occurrence of the `$end` string after that.
      *
      * @param string $string The input string.
      * @param string $start The string marking the start of the portion to extract.
-     * @param string $end The string marking the end of the portion to extract.
+     * @param string|null $end The string marking the end of the portion to extract.
+     * If the `$end` string is not provided, it defaults to the value of the `$start` string.
      * @return string|null The portion of the string between the first occurrence of
-     * start and the last occurrence of end, or null if either start or end cannot be found.
+     * `$start` and the last occurrence of `$end`, or null if either `$start` or `$end` cannot be found.
      */
     public static function findBetween($string, $start, $end)
     {
+        if ($end === null) {
+            $end = $start;
+        }
+
         $startPos = mb_strpos($string, $start);
 
         if ($startPos === false) {

tests/framework/helpers/StringHelperTest.php

@@ -532,6 +532,8 @@ public function dataProviderFindBetween()
             ['no delimiters here', 'start', 'end', null],  // no start and end
             ['start only', 'start', 'end', null], // start found but no end
             ['end only', 'start', 'end', null], // end found but no start
+            ['a1a2a3a', 'a', 'a', '1a2a3'], // same start and end
+            ['a1a2a3a', 'a', null, '1a2a3'], // end is null
             ['spécial !@#$%^&*()', 'spé', '&*()', 'cial !@#$%^'],  // Special characters
             ['من صالح هاشمی هستم', 'من ', ' هستم', 'صالح هاشمی'], // other languages
         ];