Bcrypt抛出参数不正确错误，我在user.js中追溯到该函数

userSchema.methods.comparePassword = (candidatePassword, callback) => {
  bcrypt.compare(candidatePassword, this, (err, isMatch) => {
    console.log('candidatePassword= ', candidatePassword, '&  this= ', this);
    if (err) { return callback(err); }
    callback(null, isMatch);
  });
};

   /* 
     candidatePassword=  bird
     this=  {}
     this.password=  undefined */

用户对象作为空对象返回，因此this.password未定义。我假设bcrypt.compare中的this参数引用了userschema实例。userSchema在passport.js中声明

const passport = require('passport');
const ExtractJwt = require('passport-jwt').ExtractJwt;
const JwtStrategy = require('passport-jwt').Strategy;
const LocalStrategy = require('passport-local').Strategy;

const User = require('../models/user');
const config = require('../config');

var localOptions = {
  usernameField: 'email',
};

// Verifies user by checking if a password matches the specified email during signin
var localStrategy = new LocalStrategy(localOptions, function (email, password, done) {
  User.findOne({ email:email.toLowerCase()}, function (err, user) {
    console.log('/passport.js/localStrategy- user object: ', user)
    if (err) { return done(err); }
    if (!user) { return done(null, false); }
    user.comparePassword(password, function (err, isMatch) {
      console.log('/passport.js/localStrategy- password: ', password)
      if (err) { return done(err); }
      if (!isMatch) { return done(err, false); }
      return done(null, user);
    });
  });
}); 

// ... jwt strategy ...

passport.use(localStrategy);

/* 
  user object:  { _id: 58a1018dc3f89eb5955b8638,
  email: 'bird@bird.com',
  password: '$2a$10$lAJ9hoGKt9ggfk1TISfkOedxDIs/waLB5e4PccHAKt286XCKCY0/q',
  __v: 0 } */

我不是很清楚这是什么问题，因为从mongodb返回的user对象带有加密的密码字段，而user.comparepassword()被调用...

我也用相同的模式对象注册用户。

感谢任何帮助/提示！