Sequelize associations with multiple model files - node.js

Question

(Update below)
I'm trying to set up model associations using Sequelize and the .associate method.
I have the setup below but this returns an error:
UnhandledPromiseRejectionWarning: SequelizeEagerLoadingError:
ProductMember is not associated to Product!
What am I doing wrong?
Db setup:
const { Sequelize } = require("sequelize");
const config = require("./db.config.js");
const sequelize = new Sequelize(config[process.env]);
module.exports = sequelize;
db.config.js:
module.exports = {
development: {
database: DB_NAME,
username: DB_USER,
password: DB_PASS,
dialect: DB_DRIVER,
logging: false,
options: {
host: DB_HOST,
port: DB_PORT,
pool: {},
},
},
}
/models/product.js:
const { DataTypes } = require("sequelize");
const sequelize = require("../db");
const Product = sequelize.define(
"Product",
{
id: {
type: DataTypes.INTEGER,
primaryKey: true,
autoIncrement: true,
allowNull: false,
},
name: {
type: DataTypes.STRING(255),
unique: true,
allowNull: false,
},
}
{
tableName: "products",
}
}
Product.associate = (models) => {
Product.belongsToMany(models.User, {
through: models.ProductMember,
foreignKey: "product_id",
otherKey: "user_id",
});
Product.hasMany(models.ProductMember, {
foreignKey: "product_id",
allowNull: false,
});
};
module.exports = sequelize.model("Product", Product);
models/user.js:
const { DataTypes } = require("sequelize");
const sequelize = require("../db");
const User = sequelize.define(
"User",
{
id: {
type: DataTypes.INTEGER,
primaryKey: true,
autoIncrement: true,
allowNull: false,
},
email: {
type: DataTypes.STRING(255),
allowNull: false,
unique: true,
isEmail: true,
},
username: {
type: DataTypes.STRING(15),
allowNull: false,
unique: true,
},
},
{
tableName: "users",
}
);
User.associate = (models) => {
User.belongsToMany(models.Product, {
through: models.ProductMember,
foreignKey: "user_id",
otherKey: "product_id",
});
User.hasMany(models.ProductMember, {
foreignKey: "user_id",
allowNull: false,
});
User.belongsToMany(models.Product, {
through: models.UserFavouriteProducts,
foreignKey: "user_id",
otherKey: "product_id",
});
}
module.exports = sequelize.model("User", User);
models/productMember.js:
const { DataTypes } = require("sequelize");
const sequelize = require("../db");
const ProductMember = sequelize.define(
"ProductMember",
{
id: {
type: DataTypes.INTEGER,
primaryKey: true,
autoIncrement: true,
allowNull: false,
},
isAdmin: {
type: DataTypes.BOOLEAN,
defaultValue: false,
},
},
{
tableName: "product_members",
}
);
ProductMember.associate = (models) => {
ProductMember.belongsTo(models.User);
ProductMember.belongsTo(models.Product);
};
module.exports = sequelize.model("ProductMember", ProductMember);
Update: Based on this post I updated the Db setup file to:
const fs = require('fs');
const path = require('path');
var basename = path.basename(module.filename);
const models = path.join(__dirname, '../models');
const db = {};
const Sequelize = require("sequelize");
const config = require("./db.config.js");
const sequelize = new Sequelize(config[process.env]);
fs
.readdirSync(models)
.filter(function (file) {
return (file.indexOf('.') !== 0) && (file !== basename) && (file.slice(-3) === '.js');
})
.forEach(function (file) {
var model = require(path.join(models, file))(
sequelize,
Sequelize.DataTypes
);
db[model.name] = model;
})
Object.keys(db).forEach(function (modelName) {
if (db[modelName].associate) {
db[modelName].associate(db);
}
})
db.Sequelize = Sequelize;
db.sequelize = sequelize;
module.exports = db;
Model file:
module.exports = (sequelize, Sequelize) => {
const Coupon = db.sequelize.define(
//... continue as it was
return Coupon;
}
So for the model file:
Wrapped it inside module.exports = (sequelize, Sequelize) => { }
return Coupon at the end
removed const sequelize = require("../db");
New problem: But with this new setup, Sequelize-related controller methods no longer work... For example for a controller file:
const User = require("../models/user");
const ensureLoggedIn = async (req, res, next) => {
...
const user = await User.findByPk(id);
it produces the error:
User.findByPk is not a function
I've tried adding const sequelize = require("../db"); to the controller file and then const user = await sequelize.User.findByPk(id); but that produced the same error.
I've tried adding const db = require("../db"); to the controller file and then const user = await db.sequelize.User.findByPk(id); but that produced the error "Cannot read property 'findByPk' of undefined".

Answer 1

First, you don't need to call sequelize.model to get a model that registered in Sequelize, you can just export a return value from sequelize.define:
const Product = sequelize.define(
"Product",
...
module.exports = Product;
Second, it seems you didn't call associate methods of all registered models.
Look at my answer here to get an idea of how to do it.
Update: to use models if you defined them like in my answer you need to access them like this:
const { sequelize } = require("../db");
const user = await sequelize.models.User.findByPk(id);
...