async function in the $.each callbacks

I have following code in my node script.

$('p').each(function (idx, elem) {
  var article = new Article({content: $(this).html()});
  article.save(function (err) {// do something}); // db save async function or other async function
});

mongoose.connection.close();

However, the mongoose.connection.close() will run before all the documents are saved to the database. So how can I make sure all things are done before closing the db connection?

[felixfbecker]

This is a problem with async code in general. Mongoose has support for promises, so you could do this:

var promises = [];
$('p').each(function (idx, elem) {
  var article = new Article({content: $(this).html()});
  var promise = article.save();
  promises.push(promise); // db save async function or other async function
});
Promise.all(promises)
  .then(doSomethingOnSuccess)
  .catch(doSomethingOnError)
  .finally(mongoose.connection.close);

[fb55]

Cheerio now supports iterators, so the modern way of doing this would be:

for (const elem of $('p')) {
  const article = new Article({content: $(elem).html()});
  try {
    // db save async function or other async function
    await article.save();
  } catch(err) {
    // do something with `err`
  }
}

await mongoose.connection.close();