Sequelize Many to Many Self association query to fetch non directional relations

Question

I have a model 'Boy' in which I want to create many to many self association such that boy1 and boy2 are brothers.

Model Boy

const Sequelize = require('sequelize'); 
const Boy = sequelize.define('boy', {
    name: Sequelize.STRING, 
    age: Sequelize.INTEGER, 
});

module.exports.Boy; 

M:N self association:

const Boy = require('./boy'); 
const Sequelize = require('sequelize'); 

const Brother = sequelize.define('brother', {
    id: {
        type: Sequelize.INTEGER,
        primaryKey: true,
        autoIncrement: true,
        allowNull: false
      },
}); 

Boy.belongsToMany(Boy, {through Brother, as: "Brother", foreignKey: 'brother_1_id', otherKey: 'brother_2_id'}); 

and then I want to fetch all brothers to boy1 using below query:

Boy.findByPk(id, {
      include: [
             {
                model: Boy, 
                as: "Boy", 
                attributes: ["name", "age"], 
             },
      ],
}).then( boy => console.log(boy))

Then I am adding boy2 as a brother to boy1 and boy1 as brother to boy3.

but when I am fetching brothers of boy1 using above mentioned query, I am only getting boy2 and not boy3.

Is there a way that I can define the relations so that when I fetch brothers of boy1 I would get both boy2 and boy3 ?

Answer 1

I solved this by adding following line to M:N self association:

Boy.belongsToMany(Boy, {through Brother, as: "ReverseBrother", foreignKey: 'brother_2_id', otherKey: 'brother_1_id'});

and then by including following lines in query:

Boy.findByPk(id, {
      include: [
             {
                model: Boy, 
                as: "Boy", 
                attributes: ["name", "age"], 
             },
      ],
      include: [
             {
                model: Boy, 
                as: "ReverseBrother", 
                attributes: ["name", "age"], 
             },
      ]
}).then( boy => console.log(boy))