user.comparePassword is not a function - express

Question

I got stuck on hashed password validation with bcrypt-nodejs, nodeJS (expressJS) and mongoose. User can register and code generates hashed password but when I try to validate that password with comparePassword function in login page it does not work and gives me error user.comparePassword is not a function
Here is the code:
Database:
UserSchema.pre('save', async function(next){
var user = this;
if(!user.isModified('password')) return next();
bcrypt.genSalt(SALT_WORK_FACTOR, function(err, salt){
if(err) return next(err)
bcrypt.hash(user.password, salt,null, function(err,hash){
if(err) return next(err)
user.password = hash
next()
})
})
})
UserSchema.methods.comparePassword = async function(candidatePassword, cb){
bcrypt.compare(candidatePassword, this.password, function(err, isMatch){
if(err) return cb(err);
cb(null, isMatch)
})
}
Route:
router.post('/', async (req, res) => {
try {
const {username, password} = req.body;
const user = await User.findOne({username}).lean();
if (!user) {
return res.status(404).send({
message: 'user is not registered'
});
}
if(username.trim().length < 1 && password.trim().length < 1){
return res.status(409).send({message: 'username & password is required'})
}
// if (user.password !== password) {
// return res.status(403).send({
// message: 'user password invalid'
//});
//}
user.comparePassword(password, function(err, isMatch){
if(err){
return res.status(500).send({message: err.message})
}
if(!isMatch){
return res.status(403).send({
message: 'user password invali'
});
}
req.session.user = user;
const redirectTo = '/dashboard';
if (
req.is('application/json') // request content type is json
|| // or
req.xhr // is ajax
) {
// respond with json response
return res.status(200).send({redirectTo});
}
// not ajax request
// then respond redirect header
res.redirect(redirectTo);
})

Answer 1

const mongoose = require('mongoose');
var bcrypt = require('bcrypt-nodejs');
SALT_WORK_FACTOR = 10;
const userDataModal = mongoose.Schema({
username: {
type: String,
required : true,
unique:true
},
password: {
type: String,
required : true
}
});
userDataModal.pre('save', function(next) {
var user = this;
// only hash the password if it has been modified (or is new)
if (!user.isModified('password')) return next();
// generate a salt
bcrypt.genSalt(SALT_WORK_FACTOR, function(err, salt) {
if (err) return next(err);
// hash the password using our new salt
bcrypt.hash(user.password, salt, null, function(err, hash) {
if (err) return next(err);
// override the cleartext password with the hashed one
user.password = hash;
next();
});
});
});
userDataModal.methods.comparePassword = function(candidatePassword, cb) {
bcrypt.compare(candidatePassword, this.password, function(err, isMatch) {
if (err) return cb(err);
cb(null, isMatch);
});
};
// Users.index({ emaiId: "emaiId", fname : "fname", lname: "lname" });
const userDatamodal = module.exports = mongoose.model("usertemplates" , userDataModal)
//inserting document
userDataModel.findOne({ username: reqData.username }).then(doc => {
console.log(doc)
if (doc == null) {
let userDataMode = new userDataModel(reqData);
// userDataMode.password = userDataMode.generateHash(reqData.password);
userDataMode.save({new:true}).then(data=>{
let obj={
success:true,
message: "New user registered successfully",
data:data
}
resolve(obj)
}).catch(err=>{
reject(err)
})
}
else {
resolve({
success: true,
docExists: true,
message: "already user registered",
data: doc
}
)
}
}).catch(err => {
console.log(err)
reject(err)
})
//retriving and checking
// test a matching password
user.comparePassword(requestData.password, function(err, isMatch) {
if (err){
reject({
'status': 'Error',
'data': err
});
throw err;
} else {
if(isMatch){
resolve({
'status': true,
'data': user,
'loginStatus' : "successfully Login"
});
console.log('Password123:', isMatch); // -> Password123: true
}