message: Keep empty lines between array items
diff: @@ -16,7 +16,6 @@ import {
  Token,
  concat,
  group,
  - hardline,
  ifBreak,
  indent,
  join,
  @@ -37,12 +36,9 @@ export default function ArrayExpression(
  if (!hasContents && !hasRest) {
  if (hasInnerComments(node)) {
  - return concat([
  - '[',
  - builder.tokenizeInnerComments(node, true),
  - hardline,
  - ']',
  - ]);
  + return group(
  + concat(['[', builder.tokenizeInnerComments(node, true), softline, ']']),
  + );
  } else {
  return '[]';
  }
  @@ -53,11 +49,14 @@ export default function ArrayExpression(
  if (hasContents) {
  const elements: Array<Token> = [];
  - for (const element of node.elements) {
  - if (element === undefined) {
  - elements.push('');
  + for (let i = 0; i < node.elements.length; i++) {
  + const element = node.elements[i];
  + const printed = builder.tokenize(element, node);
  +
  + if (i > 0 && builder.getLinesBetween(node.elements[i - 1], element) > 1) {
  + elements.push(concat([softline, printed]));
  } else {
  - elements.push(builder.tokenize(element, node));
  + elements.push(printed);
  }
  }
  