Develop Reference

Sequelize.build with associations

I'm creating a multipage survey with Node.js 6, Express.js 4 and Sequelize 4.4.2. While the user fills out the survey several model objects are build, but not persisted, this will not happen until the survey is completely done.
Some of these models are associated with each other and I want to know if it's possible to use the .build() function of an defined model with initial values (such as "name" or "address") as well as an previously build but not persisted model object.
Maybe a simple example, what I mean:
const comp = Company.build({
Name: 'My Company',
Location: 'Ireland',
Employees: [] // Employee would be another model in this case
});
It seems, that Employees is ignored while the obejct is built. Is there a way to attach properties which are NOT defined as field for the model (in this case: Company) but as association?
Hope you got, what I mean ...
Thank you in advance! :)

Solved it by myself! I just append the built models after to the dataValues property of the previously built model object and not directly whilst the build process.

Proper way to bind to data object in Angular 2 service?

I am building an angular 2 application. The documentation has changed quite a bit since the released which has caused confusion. The best I can do is explain what I am trying to do (Which was easy in Angular 1) and hope someone can help me out.
I have created a login service using JWT's.
Once login is successful, I return a user object.
I have a loginComponent ( binds data to template ) and loginService ( which handles the https calls )
I have a userService which maintains the user object.
I have a userComponent which renders the user data.
The problem is, once the user has logged in, I am unclear on the best approach for letting the userService retrieve the new data in an object called "user", then the userComponent update its user object on the template. This was easy in angular 1 simply by putting a watcher on the userService.user object.
I tried Inputs and Outputs to no avail, eventEmitters, Observables and getters and setters. The getters and setters work, but force me to store everything in a "val()"
Can someone please tell me the best way to achieve this?
User Component renders template with user.firstName, user.lastName etc.
Initially user if an empty Object
The login service needs to set the UserService.user
The userComponent Needs to detect the change and update the DOM.
Thanks in ADVANCE!

If I'm not wrong, you are looking for a way to 'listen' to changes in your UserService.user to make appropriate updates in your UserComponent. It is fairly easy to do that with Subject (or BehaviorSubject).
-In your UserService, declare a property user with type Subject<User>.
user: Subject<User> = new Subject();
-Expose it to outside as observable:
user$: Observable<User>
...
this.user$ = this.user.asObservable();
-Login function will update the private user Subject.
login(userName: string, password: string) {
//...
this.user.next(new User("First name", "Last name"));
}
-In your UserComponent, subscribe to UserServive's user$ observable to update view.
this.userService.user$.subscribe((userData) => {this.user = userData;});
-In your view, simply use string interpolation:
{{user?.firstName}} {{user?.lastName}}
Here is the working plunker: http://plnkr.co/edit/qUR0spZL9hgZkBe8PHw4?p=preview

There are two rather different approaches you could take:
1. Share data via JavaScript reference types
If you create an object in your UserService
#Injectable()
export class UserService {
public user = new User();
you can then share that object just by virtue of it being a JavaScript reference type. Any other service or component that injects the UserService will have access to that user object. As long as you only modify the original object (i.e., you don't assign a new object) in your service,
updateUser(user:User) {
this.user.firstName = user.firstName;
this.user.lastName = user.lastName;
}
all of your views will automatically update and show the new data after it is changed (because of the way Angular change detection works). There is no need for any Angular 1-like watchers.
Here's an example plunker.
In the plunker, instead of a shared user object, it has a shared data object. There is a change data button that you can click that will call a changeData() method on the service. You can see that the AppComponent's view automatically updates when the service changes its data property. You don't have to write any code to make this work -- no getter, setter, Input, Output/EventEmitter, or Observable is required.
The view update automatically happens because (by default) Angular change detection checks all of the template bindings (like {{data.prop1}}) each time a monkey-patched asynchronous event fires (such as a button click).
2. "Push" data using RxJS
#HarryNinh covered this pretty well in his answer. See also Cookbook topic Parent and children communicate via a service. It shows how to use a Subject to facilitate communications "within a family".
I would suggest using a BehaviorSubject instead of a Subject because a BehaviorSubject has the notion of "the current value", which is likely applicable here. Consider, if you use routing and (based on some user action) you move to a new route and create a new component, you might want that new component to be able check the "current value" of the user. You'll need a BehaviorSubject to make that work. If you use a regular Subject, the new component will have no way to retrieve the current value, since subscribers to a Subject can only get newly emitted values.
So, should we use approach 1. or 2.? As usual, "it depends". Approach 1. is a lot less code, and you don't need to understand RxJS (but you do need to understand JavaScript reference types). Approach 2. is all the rage these days.
Approach 2. could also be more efficient than 1., but because Angular's default change detection strategy is to "check all components", you would need to use the OnPush change detection strategy and markForCheck() (I'm not going to get into how to use those here) to make it more efficient than approach 1.

Get current user from inside the model in Sails

I'm using toJSON() method of my model in Sails in order to control the visibility of some of it's properties, when model is exposed via application's API.
In order to decide which properties to display and which to omit I need to know the permissions of the current user. So, how do I get the current user from inside the model? Or is there a better way (pattern) to solve this problem?
Here's some sample code I want to achieve:
toJSON: function () {
var result = {};
result.firstName = this.firstName;
result.lastName = this.lastName;
// Exposing emails only to admin users.
if (currentUser.isAdmin()) {
result.email = this.email;
}
return result;
}

Your asking about reading a session inside the model call. Currently the way sails and waterline are built you can not do this.
You can use the select property on your initial model call to restrict the columns returned. Since this would be in the context of your controller you would have access to the req object.
Here are a bunch of related questions / answers on this topic.
sails.js Use session param in model
Is it possible to access a session variable directly in a Model in SailsJS
https://github.com/balderdashy/waterline/issues/556
https://github.com/balderdashy/waterline/pull/787
Sails Google Group Discussion on the topic

understand Backbone set method and Model

All, I am a newbie of Backbone. and I am trying to understand the Model of Backone. Especially how to define a Model. so far, I didn't saw a clear or formal way about how to define a Model for backbone.
For example Let's see the set method in help doc .
set
model.set(attributes, [options])
Set a hash of attributes (one or many) on the model.
Say we have some code like below . I think set method actually is assign a javascript object to the Model.
window.Employee = Backbone.Model.extend({
validate:function(attrs){
for(var key in attrs){
if(attrs[key] == ''){
return key + "can not be null";
}
if(key == 'age' && isNaN(attrs.age)){
return "age is numeric";
}
}
}
});
....
var attr = {}; // I can't not sure what is {} mean.
$('#emp-form input,#emp-form select').each(function(){
var input = $(this);//using jquery select input and select. and enumerate all of them.
attr[input.attr('name')] = input.val();//I am not sure what does it means
});
if(employee.set(attr)){
Employees.create(employee);
}
....
in this example ,I didn't saw the classical way which we can see in java class or c# class to define the class fields or methods. but only see a validate function .Is there anybody who can tell me more about it to help me understand? thanks.

To define a model in Backbone you have to extend the Backbone.Model object. For example if you'll like to create a new User model you could write something like this:
var User = Backbone.Model.extend({})
You can also overwrite some model methods to fill your needs. For example you can change the urlRoot attribute to tell the model where should he fetch the data.
Backbone models contain your data in the attributes attribute. You change those attributes by using the model set method and you can read the value stored in the model using the get method. So if you had some inputs where a user can enter information, for example creating a new user with his name and email and you have a form with a text input for both of them. You could do domething like this:
var user = new User;
user.set('name', $('#name').val());
user.set('email', $('#email').val());
attributes = {
name: user.get('name'),
email: user.get('email')
};
user.save(attributes);
There are a lot of ways to re-factor this code to make it look better but it help to see how you could use those methods. You should check the Backbone documentation to explore how they work a little bit more. Hope this helps!
PD: In my example I set an attribute a time, but you could also send a hash of attributes to set more values in one call.

The model in JS is basically a wrapper for data, with CRUD and simple validation functions. To work properly you need to make server functions to work with (ajax), I think this tutorial says it all http://backbonetutorials.com/what-is-a-model/. Instead of database the model works with your application server side.
If you have custom actions (not just add/edit/remove) on your data, you can manually "set()" data, use "onchange" event and refresh your view when needed. You can even attach "onchange" events only on specific fields and make custom functions in your view to handle each special field (for validation or display).
You can define fields at initialize and defaults value, but not custom functions (ofc you can do model.customFuntion() but I don't recommend it.
In order to make it more "clasical way" you need to use the other Backbone functions http://backbonejs.org/#Collection-Underscore-Methods and Backbone.Collection.

Upgrading a Model (backbone.js)

Right now I have a generic User model for all users. When a user logs it's determined wether they are user type 1 or user type 2. These two types need totally different models to represent them but still include everything found in the generic User model.
My goal is up upgrade the User model for each type of user by passing the state from the current User model into the Type1 or Type2 model.
(in coffeescript)
class Type1 extends User
#add super set of methods
#user arrives
user = new User
#after logging in
state = user.toJSON()
#do I need to unbind/delete the current user model?
user = new Type1(state)
Is this the best way to achieve this?
Thanks!

You could do that. You could also just copy over the attributes:
userCopy = new Type1
userCopy.attributes = user.attributes
delete user
Note that with either approach, you'll lose event bindings, etc. A safer, more JavaScript-y approach would be to just extend user in-place with additional methods, rather than having a Type1 class at all. (Of course, there are downsides to that to, such as losing the ability to invoke super from those methods. See my answer to a similar question here.)