Sequelize bulk synchronization does nothing - node.js

Question

I'm unable to get sequelize.sync() to work. Calling sync() on each model definition works flawlessly but calling it from the sequelize instance appears do to nothing, like if the model manager had no registered models in it.
Consider the following:
function syncAll() {
console.log('Retrieving exported models...')
let models = require('./models')
for(var modelName in models) {
let model = models[modelName]
// define() just wraps a regular sequelize.define() call
// model.define().sync() works!
model.define()
}
console.log('All exported models have been defined! Syncing database...')
sequelize.sync({
logging: true
}).then(function() {
// The operation completes but no command is executed in the DB
console.log('Database synchronization complete!')
}).catch(function(error) {
console.log("Database synchronization error:\n\t${error}")
})
}
Just trying to understand what I'm missing, why bulk synchronization isn't working for me?
AFAIK I just need all models defined before calling sequelize.sync(), right?!
EDIT 1
Some info about my environment: I'm using node 5.6 under debian with postgres
EDIT 2
Found the problem. Refer to end of the accepted answer...

Answer 1

This code from sequelize example works fine for me:
var sequelize = new Sequelize(config.database, config.username, config.password, config);
var db: any = {};
var Task = sequelize.define("Task", {
title: Sequelize.STRING
}, {
classMethods: {
associate: function(models) {
Task.belongsTo(models.User, {
onDelete: "CASCADE",
foreignKey: {
allowNull: false
}
});
}
}
});
var User = sequelize.define("User", {
username: Sequelize.STRING
}, {
classMethods: {
associate: function(models) {
User.hasMany(models.Task);
}
}
});
db.User = User;
db.Task = Task;
Object.keys(db).forEach(function(modelName) {
if ("associate" in db[modelName]) {
db[modelName].associate(db);
}
});
sequelize.sync().then(() => {
// some code here
});
Models have been defined via "sequelize.define(...)" and after that "sequelize.sync()" has been called.
Update 1
I'm using sqlite:
var config: any = {
"dialect": "sqlite",
"storage": "./db.development.sqlite"
};
Update from OP
I've spotted the only diference between this code and mine. Due to a bug in my logic sequelize.define() and sequelize.sync() were being called from different sequelize instances (i.e different connections) and each connection has its own modelManager so obviously there was no models to sync in the second connection object.