Nested associated data through Sequelize join tables - node.js

Question

Using Sequelize, I'm trying to get an output like this:
[{
"Id": 1,
"Name": "Game 1",
"Teams": [{
"Id": 1,
"Name": "Team 1",
"Users": [{
"Id": 1,
"UserName": "User 1"
}]
}]
}, {
"Id": 2,
"Name": "Game 2",
"Teams": [{
"Id": 1,
"Name": "Team 1",
"Users": [{
"Id": 2,
"UserName": "User 2"
}]
}]
}]
Note that Team 1 has 2 different users, but that's only because they're set up that way per game... so a user isn't tied directly to a team, but rather through a team game constraint. Basically, my Game HasMany Teams, and my Game/Team HasMany Users... a many-to-many-to-many relationship. I was trying to follow this thread, but it seems like what they're doing there doesn't actually work, as I tried doing this:
// models/Game.js
module.exports = (sequelize, types) => {
const GameModel = sequelize.define('Game', {
Id: {
type: types.INTEGER,
primaryKey: true,
autoIncrement: true
},
Name: {
type: types.STRING,
allowNull: false
}
});
GameModel.associate = (models) => {
GameModel.belongsToMany(models.Team, {
as: 'Teams',
foreignKey: 'GameId',
through: models.GameTeam
});
};
return GameModel;
};
// models/Team.js
module.exports = (sequelize, types) => {
const TeamModel = sequelize.define('Team', {
Id: {
type: types.INTEGER,
primaryKey: true,
autoIncrement: true
},
Name: {
type: types.STRING,
allowNull: false
}
});
TeamModel.associate = (models) => {
TeamModel.belongsToMany(models.Game, {
as: 'Games',
foreignKey: 'TeamId',
through: models.GameTeam
});
};
return TeamModel;
};
// models/User.js
module.exports = (sequelize, types) => {
const UserModel = sequelize.define('User', {
Id: {
type: types.INTEGER,
primaryKey: true,
autoIncrement: true
},
UserName: {
type: types.STRING,
allowNull: false
}
});
return UserModel;
};
// models/GameTeam.js
module.exports = (sequelize, types) => {
const GameTeamModel = sequelize.define('GameTeam', {
Id: {
type: types.INTEGER,
primaryKey: true,
autoIncrement: true
}
});
GameTeamModel.associate = (models) => {
GameTeamModel.belongsToMany(models.User, {
as: 'Users',
through: 'GameTeamUser'
});
};
return GameTeamModel;
};
The above models create the tables just fine, with what appears to be the appropriate columns. I then do some inserts and try to use a findAll on the Game model like this:
GameModel.findAll({
include: [{
association: GameModel.associations.Teams,
include: [{
association: GameTeamModel.associations.Users,
through: {
attributes: []
}
}],
through: {
attributes: []
}
}]
});
The query starts to go wrong at the 2nd include with the association of the Users. Because I'm trying to nest the users inside of the teams, I figured the join would attempt to use the unique ID on the through table (GameTeams.Id), but instead, the query ends up using this:
LEFT OUTER JOIN `GameTeamUser` AS `Teams->Users->GameTeamUser` ON `Teams`.`Id` = `Teams->Users->GameTeamUser`.`GameTeamId`
I figured the ON would be GameTeams.Id = Teams->Users->GameTeamuser.GameTeamId, but I don't know why it's not, and how to adjust it... I've tried using a custom on in my include (per the docs), but it seems to be ignored completely. Anyone have any advice? Or possibly a better way of structuring this, so it works the way I want it to?

Answer 1

I think you are overcomplicating this thinking you have a many to many to many..and i can see that the fields for your model for GameTeam do not match up with the foreign keys you have declared in your other models...
What do your database tables look like?
Am i correct in saying, that a game has many teams, and a team has many users... however a user can only be on one team at a time, and a team is only in one game at a time? (i am assuming the game/team join and the team/user join are simply temporary records in the join tables disappearing after the game is over etc)