src/language-js/print/decorators.js/printDecoratorsBeforeExport
function printDecoratorsBeforeExport(path, options, print) {
  // Export declarations are responsible for printing any decorators
  // that logically apply to node.declaration.
  return [
    join(hardline, path.map(print, "declaration", "decorators")),
    hardline,
  ];
}