Ternary association with same table - sql

Question

I would like to make 2 tables and setup associations between them to have something that looks like this : https://i.stack.imgur.com/hFjCP.png
I'm not really sure but it looks like a ternary association where 2 columns are from the same table. Both player1 and player2 are of type User.
I tried something like this but I'm really not sure this is the way to go.
const User = sequelize.define('User', { id: DataTypes.STRING })
const Battle = sequelize.define('Battle', { id: DataTypes.STRING })
const UserBattleParticipation = sequelize.define('UserBattleParticipation', {
battleId: {
type: DataTypes.STRING,
primaryKey: true,
allowNull: false,
references: {
model: Battle,
key: 'id'
}
},
player1: {
type: DataTypes.STRING,
primaryKey: true,
allowNull: false,
references: {
model: User,
key: 'id'
}
},
player2: {
type: DataTypes.STRING,
primaryKey: true,
allowNull: false,
references: {
model: User,
key: 'id'
}
},
additional: {
type: DataTypes.STRING,
allowNull: false
}
})
Battle.belongsToMany(User, { as: 'Participant', through:UserBattleParticipation, foreignKey: { name: 'battleId', allowNull: false} });
User.belongsToMany(Battle, { as: 'Attacker', through:UserBattleParticipation, foreignKey: { name: 'player1', allowNull: false } });
User.belongsToMany(Battle, { as: 'Target', through: UserBattleParticipation, foreignKey: { name: 'player2', allowNull: false } });

Answer 1

I suppose you turned upside down meanings of concrete associations:
// If you want to get a list of attackers in a certain battle you should define such association:
// I recommend to use aliases in plural because it's many-to-`many`
Battle.belongsToMany(User, { as: 'Attackers', through:UserBattleParticipation, foreignKey: { name: 'battleId', allowNull: false }, otherKey: { name: 'player1', allowNull: false } });
// If you want to get a list of battle where a user was as an attacker you should define such association:
User.belongsToMany(Battle, { as: 'AttackerBattles', through:UserBattleParticipation, foreignKey: { name: 'player1', allowNull: false }, otherKey: { name: 'battleId', allowNull: false } });
You cannot define an association to get all participants of a battle because you have two different columns for a user.
If you you have a predefined list of users who are participating in a certain battle then you maybe should change your structure and add Participants (ParticipantId, BattleId, UserId) and use it in BattleParticipants (BattleId, ParticipantId1, ParticipantId2, other fields).