SlevomatCodingStandard\Helpers\TokenHelper::findPreviousEffective PHP Method

    public static function findPreviousEffective(PHP_CodeSniffer_File $phpcsFile, $startPointer, $endPointer = null)
    {
        return self::findPreviousExcluding($phpcsFile, self::$ineffectiveTokenCodes, $startPointer, $endPointer);
    }

 /**
  * @param \PHP_CodeSniffer_File $phpcsFile
  * @param integer $stackPointer
  */
 public function process(PHP_CodeSniffer_File $phpcsFile, $stackPointer)
 {
     $tokens = $phpcsFile->getTokens();
     $arrayToken = $tokens[$stackPointer];
     $closeParenthesisPointer = $arrayToken['bracket_closer'];
     $openParenthesisToken = $tokens[$arrayToken['bracket_opener']];
     $closeParenthesisToken = $tokens[$closeParenthesisPointer];
     if ($openParenthesisToken['line'] === $closeParenthesisToken['line']) {
         return;
     }
     $previousToCloseParenthesisPointer = TokenHelper::findPreviousEffective($phpcsFile, $closeParenthesisPointer - 1);
     $previousToCloseParenthesisToken = $tokens[$previousToCloseParenthesisPointer];
     if ($previousToCloseParenthesisToken['code'] !== T_COMMA && $closeParenthesisToken['line'] !== $previousToCloseParenthesisToken['line']) {
         $fix = $phpcsFile->addFixableError('Multiline arrays must have a trailing comma after the last element', $previousToCloseParenthesisPointer, self::CODE_MISSING_TRAILING_COMMA);
         if ($fix) {
             $phpcsFile->fixer->beginChangeset();
             $phpcsFile->fixer->addContent($previousToCloseParenthesisPointer, ',');
             $phpcsFile->fixer->endChangeset();
         }
     }
 }