How to implement many to many association using through in Sails? - node.js

Question

I'm using Sails v0.11.2 and MongoDB 3.2 on Mac OS X El Capitan and I'm trying to implement Many-To-Many association using Through option which isn't supported yet.
However, googling I found this Waterline Github Issue and elennaro, a github user, gave me a couple of links with some examples:
First one
Second one
I have tried to adapt them to my own Sails app but I can't make it works. I got no errors on the console but the record or document on the intermediary table is not created only the Form document in it's table.
These are my models:
User.js
module.exports = {
schema: true,
tableName: 'users',
autoCreatedAt: false,
autoUpdatedAt: false,
attributes:
{
email : { type: 'email', required: true, unique: true },
encrypted_password : { type: 'string' },
reset_password_token: { type: 'string', defaultsTo: null},
permission_level : { type: 'integer', required: true, min: 1, max: 3, defaultsTo: 0 },
belongs_to : { type: 'string', required: true, defaultsTo: 0 },
signin_count : { type: 'integer', required: true, defaultsTo: 1 },
status_active : { type: 'boolean', required: true, defaultsTo: false },
last_signin_at : { type: 'datetime', defaultsTo: function (){ return new Date(); } },
last_signin_ip : { type: 'string', defaultsTo: '0.0.0.0' },
// Add a reference to Person
person_id:
{
model: 'person'
},
// Add a reference to Forms collection
forms:
{
collection: 'form',
via: 'user_id',
through: 'userhasform'
},
has:
{
collection: 'userhasform',
via: 'form_id'
}
}
};
Form.js
module.exports = {
schema: true,
tableName: 'forms',
attributes:
{
name : { type: 'string', required: true, unique: true },
creator : { type: 'string', unique: false },
sequence: { type: 'integer', autoIncrement: true },
// Add a reference to Questions collection
questions:
{
collection: 'question',
via: 'form_id'
},
// Add a reference to the owners Users
owners: {
collection: 'user',
via: 'form_id',
through: 'userhasform'
}
}
};
UserHasForm.js
module.exports = {
schema: true,
tableName: 'users_have_forms',
attributes:
{
to_edit : { type: 'boolean' },
to_delete : { type: 'boolean' },
user_id : { model: 'user' },
form_id : { model: 'form' }
}
};
The controller in which I create a form and it is supposed the intermediary document is been created at the join table is:
FormController.js
module.exports = {
create: function (req, res)
{
var ownerJson = {},
tmpFolio;
// Get the logged user to make the Folio and then create the form
SessionService.getUser(req, createForm);
// Callback function
function createForm (err, session)
{
// If there's no logged user or any error
if (err || !session)
{
console.log(err);
return res.json(err.status, {error: err});
}
console.log('User to create Folio: ', session.id);
ownerJson.owner_a = session.first_name;
ownerJson.owner_b = session.second_name;
ownerJson.owner_c = session.last_name;
// Construct the Folio creator part like AVC
tmpFolio = FolioService.generateFolio(ownerJson);
Form.create({
name: req.body.name,
creator: tmpFolio
})
.then(function (form){
if (err)
{
console.log(err);
return res.json(err.status, {error: err});
}
// Create the jointable record
var createdRecord = UserHasForm.create({
to_edit: true,
to_delete: true,
user_id: session.id,
form_id: form.id
})
.then(function (createdRecord){
if (err)
{
console.log(err);
return res.json(err.status, {error: err});
}
return createdRecord;
});
return [form, createdRecord];
})
.spread(function (form, createdRecord){
return res.json(200,
{
message: 'The form was created successfuly!',
data: form,
sharing: createdRecord
});
})
.fail(function (err){
if (err)
{
console.log(err);
res.json(err.status, {error: err});
}
});
}
},
};
When I run this code I got the next error:
[ReferenceError: UserHasForm is not defined]
Unhandled rejection TypeError: Cannot read property 'toString' of undefined
So I suppose it can't find the model so I add the next line to the model at the beginning:
var UserHasForm = require('../models/UserHasForm');
And now I get the next error:
[TypeError: UserHasForm.create is not a function]
All this is following the the first example on the list.
Any idea why I'm getting this error?
Any kind of help will be welcomed!

Answer 1

Well after trying to many examples finally I found the solution thanks to #elennaro for all his support. The whole conversation could be found in the link to the chat we both started under the main question's comments.
Also I can tell you that the examples in the links provided by him (which are in the question above) works fine, the problem was that the version I was using didn't support the features that those examples show.
Basically what I had to do is to install the most recent version for NodeJS, SailsJS and Waterline.
In my case I actually have the next ones:
Node v5.3.0
Sails v0.11.3
Waterline v0.10.30
After that I have to make some changes to my models and at the end they look like this:
User.js
module.exports = {
schema: true,
tableName: 'users',
autoCreatedAt: false,
autoUpdatedAt: false,
attributes:
{
// username : { type: 'string', unique: true, minLength: 5, maxLength: 15 },
email : { type: 'email', required: true, unique: true },
encrypted_password : { type: 'string' },
reset_password_token: { type: 'string', defaultsTo: null},
permission_level : { type: 'integer', required: true, min: 1, max: 3, defaultsTo: 0 },
belongs_to : { type: 'string', required: true, defaultsTo: 0 },
signin_count : { type: 'integer', required: true, defaultsTo: 1 },
status_active : { type: 'boolean', required: true, defaultsTo: false },
last_signin_at : { type: 'datetime', defaultsTo: function (){ return new Date(); } },
last_signin_ip : { type: 'string', defaultsTo: '0.0.0.0' },
// Add a reference to Forms collection
forms:
{
collection: 'form',
via: 'user',
through: 'userhasform'
// dominant: true
}
}
};
Form.js
module.exports = {
schema: true,
tableName: 'forms',
attributes:
{
name : { type: 'string', required: true, unique: true },
creator : { type: 'string', unique: false },
sequence: { type: 'integer', autoIncrement: true },
// Add a reference to the owners Users
owners: {
collection: 'user',
via: 'form',
through: 'userhasform'
}
}
};
UserHasForm.js
module.exports = {
schema: true,
tableName: 'users_have_forms',
attributes:
{
to_edit : { type: 'boolean' },
to_delete : { type: 'boolean' },
user : { model: 'User', foreignKey: true, columnName: 'user_id' },
form : { model: 'Form', foreignKey: true, columnName: 'form_id' }
}
};
FormController.js
Still the same as in the question
I hope it could be useful for anybody. And once again thanks to # Alexander Arutinyants for your support!
Any question, please leave a comment!