PhpCsFixer\Fixer\ArrayNotation\TrailingCommaInMultilineArrayFixer::fixArray PHP Method

    private function fixArray(Tokens $tokens, $index)
    {
        $tokensAnalyzer = new TokensAnalyzer($tokens);
        if (!$tokensAnalyzer->isArrayMultiLine($index)) {
            return;
        }
        $startIndex = $index;
        if ($tokens[$startIndex]->isGivenKind(T_ARRAY)) {
            $startIndex = $tokens->getNextTokenOfKind($startIndex, array('('));
            $endIndex = $tokens->findBlockEnd(Tokens::BLOCK_TYPE_PARENTHESIS_BRACE, $startIndex);
        } else {
            $endIndex = $tokens->findBlockEnd(Tokens::BLOCK_TYPE_ARRAY_SQUARE_BRACE, $startIndex);
        }
        $beforeEndIndex = $tokens->getPrevMeaningfulToken($endIndex);
        $beforeEndToken = $tokens[$beforeEndIndex];
        // if there is some item between braces then add `,` after it
        if ($startIndex !== $beforeEndIndex && !$beforeEndToken->equalsAny(array(',', array(T_END_HEREDOC)))) {
            $tokens->insertAt($beforeEndIndex + 1, new Token(','));
            $endToken = $tokens[$endIndex];
            if (!$endToken->isComment() && !$endToken->isWhitespace()) {
                $tokens->ensureWhitespaceAtIndex($endIndex, 1, ' ');
            }
        }
    }