Join is not working for sequelize associations belongsToMany - mysql

Question

I am testing all the associations with sequelize and I am getting a problem to get joins for many to many with belongsToMany.
https://github.com/lhferrh/Sequelize-Playground.git
When I do the findAll through I get the all null for the join result
I have been checking several combinations but the thing is that the SQL produced by sequelize is working on MySQL directly and it makes me really confused.
This is the sql provided:
SELECT `user`.`userId`, `user`.`name`, `user`.`createdAt`, `user`.`updatedAt`, `cars`.`carId` AS `cars.carId`, `cars`.`make` AS `cars.make`, `cars`.`createdAt` AS `cars.createdAt`, `cars`.`updatedAt` AS `cars.updatedAt`, `cars->favorites`.`favoritesId` AS `cars.favorites.favoritesId`, `cars->favorites`.`date` AS `cars.favorites.date`, `cars->favorites`.`createdAt` AS `cars.favorites.createdAt`, `cars->favorites`.`updatedAt` AS `cars.favorites.updatedAt`, `cars->favorites`.`userId` AS `cars.favorites.userId`, `cars->favorites`.`carId` AS `cars.favorites.carId` FROM `users` AS `user` LEFT OUTER JOIN ( `favorites` AS `cars->favorites` INNER JOIN `cars` AS `cars` ON `cars`.`carId` = `cars->favorites`.`carId`) ON `user`.`userId` = `cars->favorites`.`userId`;
This is the code I am running:
const Users = sequelize.define('user', {
userId: {
type: Sequelize.INTEGER,
allowNull: false,
primaryKey: true,
autoIncrement: true
},
name: {
type: Sequelize.STRING,
},
}
);
const Favorites = sequelize.define('favorites', {
favoritesId: {
type: Sequelize.INTEGER,
allowNull: false,
primaryKey: true,
autoIncrement: true
},
date: {
type: Sequelize.DATE,
}
}
);
const Cars = sequelize.define('cars', {
carId: {
type: Sequelize.INTEGER,
primaryKey: true,
autoIncrement: true
},
make: Sequelize.STRING
})
Users.belongsToMany(Cars, {
through: 'favorites',
sourceKey: 'userId',
foreignKey: 'userId'
});
Cars.belongsToMany(Users, {
through: 'favorites',
sourceKey: 'carId',
foreignKey: 'carId'
});
const intiDataBase = async () => {
await sequelize.sync({force: true});
}
const run = async () => {
const max = 3;
await intiDataBase();
await Promise.all( DATA.users.map( async elem=>
Users.create({...elem})
))
await Promise.all( DATA.cars.map( async elem =>
Cars.create({...elem})
))
for( let i = 0 ; i < 5 ; i++ ){
Favorites.create({
userId: getRandomInt(1 , max),
carId: getRandomInt(0, max)
})
}
const car = await Users.findAll({
include: [{
model: Cars,
through: {
attributes: ['userId', 'carId'],
}
//attributes: ['make'],
}],
raw: true
});
const favorites = await Favorites.findAll({
where:{
userId:2
},
raw: true
});
console.log(car);
console.log(favorites);
}
run();
This is result I get:
name: 'Johan',
createdAt: 2019-10-05T08:57:57.000Z,
updatedAt: 2019-10-05T08:57:57.000Z,
'cars.carId': null,
'cars.make': null,
'cars.createdAt': null,
'cars.updatedAt': null,
'cars.favorites.favoritesId': null,
'cars.favorites.date': null,
'cars.favorites.createdAt': null,
'cars.favorites.updatedAt': null,
'cars.favorites.userId': null,
'cars.favorites.carId': null } ], ...
Probably this is a naming problem but the fact the SQL is working directly makes is really confusing.
I hope any of you can see the error.
By the way, I was also wondering what would be the disadvantage of creating the many to many relationship manually by creating two 1:m associations to the intermediate table?

Answer 1

I found my error. There is an await missing when I am inserting favorites to the database. For that reason the join was giving the the wrong result in the query and the correct one in the database directly.
for( let i = 0 ; i < 5 ; i++ ){
await Favorites.create({
userId: getRandomInt(1 , max),
carId: getRandomInt(0, max)
})
}
As I was expecting, a silly error.
Anyways I am still hesitant about using belongToMany or creating the many to many relationship by myself and use always two steps.