class DuplicatePropertySniff

class DuplicatePropertySniff implements Sniff {
    
    /**
     * A list of tokenizers this sniff supports.
     *
     * @var array
     */
    public $supportedTokenizers = [
        'JS',
    ];
    
    /**
     * Returns an array of tokens this test wants to listen for.
     *
     * @return array<int|string>
     */
    public function register() {
        return [
            T_OBJECT,
        ];
    }
    
    //end register()
    
    /**
     * Processes this test, when one of its tokens is encountered.
     *
     * @param \PHP_CodeSniffer\Files\File $phpcsFile The current file being processed.
     * @param int                         $stackPtr  The position of the current token in the
     *                                               stack passed in $tokens.
     *
     * @return void
     */
    public function process(File $phpcsFile, $stackPtr) {
        $tokens = $phpcsFile->getTokens();
        $properties = [];
        $wantedTokens = [
            T_PROPERTY,
            T_OBJECT,
        ];
        $next = $phpcsFile->findNext($wantedTokens, $stackPtr + 1, $tokens[$stackPtr]['bracket_closer']);
        while ($next !== false && $next < $tokens[$stackPtr]['bracket_closer']) {
            if ($tokens[$next]['code'] === T_OBJECT) {
                // Skip nested objects.
                $next = $tokens[$next]['bracket_closer'];
            }
            else {
                $propName = $tokens[$next]['content'];
                if (isset($properties[$propName]) === true) {
                    $error = 'Duplicate property definition found for "%s"; previously defined on line %s';
                    $data = [
                        $propName,
                        $tokens[$properties[$propName]]['line'],
                    ];
                    $phpcsFile->addError($error, $next, 'Found', $data);
                }
                $properties[$propName] = $next;
            }
            
            //end if
            $next = $phpcsFile->findNext($wantedTokens, $next + 1, $tokens[$stackPtr]['bracket_closer']);
        }
        
        //end while
    }
    
    //end process()

}