使用Passport注册时遇TypeError: cb is not a function错误怎么解决？

问题 #

使用Passport实现用户注册功能时，页面弹出TypeError: cb is not a function错误，控制台报错日志如下：

node_modules\passport-local-mongoose\index.js:247
    promise.then((result) => cb(null, result)).catch((err) => cb(err));
                                                              ^

TypeError: cb is not a function

对应注册代码：

router.post(
  "/register",
  catchAsync(async (req, res, next) => {
    const { username, password, email, number, address } = req.body.user;
    const user = new User({
      email,
      username,
      number,
      address,
      isVerified: false,
    });
    const registredUser = await User.register(user, username, password);
    req.login(registredUser, (err) => {
      if (err) {
        return next(err);
      }
      console.log(registredUser);
      req.flash("success", "Dobro došli na About Women!");
      res.redirect("users/confirm");
    });
  })
);

修复方法 #

错误根源是User.register()的参数传递不符合passport-local-mongoose的要求。该方法的正确参数格式为User.register(userInstance, password, [callback])，你多传入了一个username参数，导致方法误将password识别为回调函数，从而触发cb is not a function错误。

修改后的代码：

router.post(
  "/register",
  catchAsync(async (req, res, next) => {
    const { username, password, email, number, address } = req.body.user;
    const user = new User({
      email,
      username,
      number,
      address,
      isVerified: false,
    });
    // 移除多余的username参数
    const registredUser = await User.register(user, password);
    req.login(registredUser, (err) => {
      if (err) {
        return next(err);
      }
      console.log(registredUser);
      req.flash("success", "Dobro došli na About Women!");
      res.redirect("users/confirm");
    });
  })
);

说明：创建User实例时已经传入了username，register方法会直接从该实例中读取用户名信息，无需额外传递。

内容的提问来源于stack exchange，提问作者Impra