In sequelize, how to query the model associated with 'through' - associations

Question

I am very new to Sequelize and need help to create a method to query between two tables.
I have given three models named "user", "project" and "user_project".
user_project stores the relationship between users and projects. It uses two foreign keys (user_id and project_id) from other tables.
In addition, user_project has a field named "role" to specify the role of the user in a project. I am trying to figure out a way to extract user roles based on user "email". Note than user email is stored in user table.
The associations between them are as follows:
models.project.belongsToMany(models.user, {
through: models.user_project,
foreignKey: {
name: 'projectId',
field: 'project_id'
}
});
models.user.belongsToMany(models.project, {
through: models.user_project,
foreignKey: {
name: 'userId',
field: 'user_id'
}
});
Thanks in advance.

Answer 1

Know this is very late but hope it will someone else in future -
Using raw query and then converting the roles string to array -
User.findOne({
where: {email},
attributes: [
'id', 'email',
[Sequelize.literal("(SELECT GROUP_CONCAT(roles) FROM user_project UP WHERE UP.user_id=user.id )"), "roles"],
]
}).then( (user) => {
if(!user)
return null;
user = JSON.parse(JSON.stringify(user));
if(!user.roles)
user.roles = [];
else
user.roles = user.roles.split(",");
return user;
});
Getting roles without Using Raw -
User.findOne({
where: {email},
attributes: [
'id', 'email'
],
include: [
{
model: Db.user_project,
required: false,
attributes: ["user_id", "roles"]
}
]
}).then( (user) => {
if(!user)
return null;
user = JSON.parse(JSON.stringify(user));
if(!user.roles)
user.roles = [];
else
user.roles = user.roles.map(r => r.roles);
return user;
});