code: private function fixSpacing($index, Tokens $tokens)
      {
          if ($tokens[$index]->isGivenKind(CT::T_ARRAY_SQUARE_BRACE_OPEN)) {
              $startIndex = $index;
              $endIndex = $tokens->findBlockEnd(Tokens::BLOCK_TYPE_ARRAY_SQUARE_BRACE, $startIndex);
          } else {
              $startIndex = $tokens->getNextTokenOfKind($index, ['(']);
              $endIndex = $tokens->findBlockEnd(Tokens::BLOCK_TYPE_PARENTHESIS_BRACE, $startIndex);
          }
  
          for ($i = $endIndex - 1; $i > $startIndex; --$i) {
              $i = $this->skipNonArrayElements($i, $tokens);
              $currentToken = $tokens[$i];
              $prevIndex = $tokens->getPrevNonWhitespace($i - 1);
              if ($currentToken->equals(',') && !$tokens[$prevIndex]->equals([T_END_HEREDOC]) && !$tokens[$prevIndex]->isComment()) {
                  $tokens->removeLeadingWhitespace($i);
              }
          }
      }
docs: Method to fix spacing in array declaration.
  
  @param int    $index
  @param Tokens $tokens