如何在mongoose中使用异步查找方法？

Question

这是我目前使用express.js编写的代码。

＆＃13;

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const router = express.Router();

router.post('/', async (req, res) => {
 const username = '';
  await User.findOne({_id: req.body.id,}, (err, user) => {
  if (err) // how to process this part?
  username = user.username;
  });
});

＆＃13;

＆＃13;

＆＃13;

Answer 1

您可以return功能user.username .findOne()。请注意，无法重新分配使用const声明的变量标识符，请参阅Is it possible to delete a variable declared using const?。

const router = express.Router();

router.post('/', async (req, res) => {
  const username = await User.findOne({_id: req.body.id,}, (err, user) => {
    // return empty string or other value if `err`
    if (err) return "" // how to process this part?
    return user.username;
  });
});