Unable to develop assosciations between models in sequelize - node.js

Question

I am creating realtionship (one to many) between User model and Task model
I have crated the reference column in the migration too
I am using sequlize ORM with sequelize cli. Everything works fine when I try alternative method that i will explain later but If i try to do it according the documentation it gives me error
Task is not associated to User
WORKING ALTERNATIVE METHOD
IN end of index.js file I created relations and it works as expected
db.user = require("../models/user.js")(sequelize, Sequelize);
db.tasks = require("../models/Task.js")(sequelize, Sequelize);
db.user.hasMany(db.tasks, { as: "user_tasks",foreignKey: "userId" });
db.tasks.belongsTo(db.user, {
foreignKey: "userId",
as: "task_user",
});
but when i follow the documetation i got error that i mentioned earlier
According to document
Model User.js
module.exports = (sequelize, DataTypes) => {
const User =sequelize.define('User',{
id: {
type: DataTypes.INTEGER,
autoIncrement: true,
allowNull: false,
primaryKey: true,
},
name: {
type: DataTypes.STRING,
allowNull: false,
},
age: {
type: DataTypes.INTEGER,
},
email: {
type: DataTypes.STRING,
},
createdAt: {
allowNull: false,
type: DataTypes.DATE
},
updatedAt: {
allowNull: false,
type: DataTypes.DATE
}
});
User.associate = (models) =>{
User.hasMany(models.Tasks, {
as: 'user_tasks',
foreignKey: 'userId'}
);
};
return User;
};
Model: Task.js
module.exports = (sequelize, DataTypes) => {
const Task = sequelize.define('Task', {
id: {
type: DataTypes.INTEGER,
autoIncrement: true,
allowNull: false,
primaryKey: true,
},
title: {
type: DataTypes.STRING,
allowNull: false,
},
userId: {
type: DataTypes.INTEGER,
},
});
Task.associate = function(models) {
Task.belongsTo(models.User, {
as:'owner',
foreignKey:'userId',
onDelete: "cascade"
});
};
return Task;
}
This is how i am trying to get data from database
controller
const User = db.user
const {Tasks} = db.tasks
exports.usertasks = async(req,res)=>{
// const users = await User(db.sequelize,db.Sequelize).findAll({
const users = await User.findAll({
include:[{model:Tasks,as:"user_tasks"}]
});
res.json(users)
console.log("All users with their associated tasks:", JSON.stringify(users, null, 4));
}
My Index.js file
'use strict';
const fs = require('fs');
const path = require('path');
const Sequelize = require('sequelize');
const basename = path.basename(__filename);
const env = process.env.NODE_ENV || 'development';
const config = require(__dirname + '/../config/config.json')[env];
const db = {};
let sequelize;
if (config.use_env_variable) {
sequelize = new Sequelize(process.env[config.use_env_variable], config);
} else {
sequelize = new Sequelize(config.database, config.username, config.password, config);
}
fs
.readdirSync(__dirname)
.filter(file => {
return (file.indexOf('.') !== 0) && (file !== basename) && (file.slice(-3) === '.js');
})
.forEach(file => {
const model = require(path.join(__dirname+'../models/', file))(sequelize, Sequelize.DataTypes);
console.log(model);
db[model.name] = model;
});
Object.keys(db).forEach(modelName => {
if (db[modelName].associate) {
db[modelName].associate(db);
}
});
db.sequelize = sequelize;
db.Sequelize = Sequelize;
//relations THIS IS WORKING AND I AM JUST CURIOUS WHETHER TO USE THIS APPROACH OR NOT
// db.user = require("../models/user.js")(sequelize, Sequelize);
// db.tasks = require("../models/Task.js")(sequelize, Sequelize);
// db.user.hasMany(db.tasks, { as: "user_tasks",foreignKey: "userId" });
// db.tasks.belongsTo(db.user, {
// foreignKey: "userId",
// as: "task_user",
// });
module.exports = db;
I am also attaching the picture of successful response that I get with the alternative method.
Kindly, guide whether the alternative method that I used is acceptable or should I stick to the documenation one?

Answer 1

.associate is not a native Model's method, so you need to call it manually.
I think in your index.js you want to do something like:
'use strict';
const Sequelize = require('sequelize');
const config = require('../config/config.json')[process.env.NODE_ENV || 'development'];
const requireAll = require('require-all');
const sequelize = config.use_env_variable
? new Sequelize(process.env[config.use_env_variable], config)
: new Sequelize(config.database, config.username, config.password, config);
const db = { sequelize };
const modelsInitializers = Object.values(requireAll({
dirname: __dirname,
recursive: false,
filter: (name) => name !== 'index.js' && name,
}));
const models = modelsInitializers.map((initializer) => {
const model = initializer(sequelize, Sequelize.DataTypes);
db[model.name] = model;
return model;
});
models.forEach((model) => {
if (model.associate) model.associate(db);
})
models.forEach((model) => {
if (model.associate) model.associate(models);
db[model.name] = model;
})
Object.entries().forEach(([modelName, model]) => {
model.associate(models);
db[modelName] = model;
});
module.exports = db;