Node.js如何在for或foreach中從MongoDB中進行選擇？

Question

我有以下代碼：

result.rides.forEach(function(ride) {
      var query = {
        "by.phone": req.body.myPhone,
        "inRide": ride["_id"].toString(),
      };
      db.offers.findOne(query, function(err, docs) {
        if (docs) {
          ride.offered = true;
        }
      });
    });

現在，我想在forEach的末尾返回result.rides，該怎么做？

Answer 1

將每個迭代到它自己的awaitable ，等待他們全部完成如

async func() {
  const queries = result.rides.map(r =>
    new Promise(async (resolve, reject) => {
      try {
        const query = {
          'by.phone': req.body.myPhone,
          'inRide': r._id.toString()
        };
        const docs = await db.offers(query);
        if (docs) {
          r.offered = true;
        }
        return resolve();
      } catch (e) {
        return reject(e);
      }
    })
  );
  await Promise.all(queries);
  // do something with rides
}