src/language-js/print/array.js/printArrayItems
function printArrayItems(path, options, printPath, print) {
  const printedElements = [];
  let separatorParts = [];

  path.each((childPath) => {
    printedElements.push(concat(separatorParts));
    printedElements.push(group(print(childPath)));

    separatorParts = [",", line];
    if (
      childPath.getValue() &&
      isNextLineEmpty(options.originalText, childPath.getValue(), locEnd)
    ) {
      separatorParts.push(softline);
    }
  }, printPath);

  return concat(printedElements);
}