Make a programmatically Created Controller Delegate (Bubble) Events - ember.js

I have an app with many similar views which I instantiate programmatically to "DRY-up" my app.
The problem is that controllers instantiated programmatically do not delegate actions in the actions hash further. This is clear because there is nothing from which the controller can derive the hierarchy. There should be a way, however, to tell a controller which parent controller it has to use for event bubbling. Does anyone know it?

You shouldn't be initializing controller's on your own. All controller initialization should be handled by Ember itself. Another interesting note, controller's are intended to be singletons in the application. The only exception to this being the itemController when looping over an ArrayController. You can read more about it in the guides. Quote from the guides:
In Ember.js applications, you will always specify your controllers as
classes, and the framework is responsible for instantiating them and
providing them to your templates.
This makes it super-simple to test your controllers, and ensures that
your entire application shares a single instance of each controller.
Update 1:
An example of how to do routing for a wizard:
App.Router.map(function() {
this.resource('wizard', function() {
this.route('step1');
this.route('step2');
this.route('step3');
});
});
This way, you can have a separate controller/view/template per step of the wizard. If you have logic around how much of each step should be completed prior to transitioning to the next one, you can handle that in the individual routes.
Update 2:
In the event that the number of steps aren't predetermined, but are based on the data being fed to the app, you can make a WizardController that is an ArrayController where each item in the array is a step in the wizard. Then, use the lookupItemController hook on the ArrayController, kind of like this:
App.WizardRoute = Ember.Route.extend({
model: function() {
return [
{controllerName: 'step1', templateName: 'step1'},
{controllerName: 'step2', templateName: 'step2'},
{controllerName: 'step3', templateName: 'step3'}
];
}
});
App.WizardController = Ember.ArrayController.extend({
lookupItemController: function(modelObject) {
return modelObject.controllerName;
}
});
{{#each step in controller}}
{{view Ember.View templateName=step.templateName}}
{{/each}}
As another, probably better, alternative, you can override the renderTemplate hook in the route where you're pulling down the model for the next step in the wizard and pass in the appropriate templateName and controller in the render call, kind of like you see here.
Point being, I think it should be possible to do this without having to instantiate controllers yourself.

Related

How to run an action on every route transition in ember?

I have an Ember application with several routes and I want to scroll the page to top every time the user makes a transition. The problem is that I don't want to duplicate the same code on every route's didTransitionmethod.
So, Is there a way that I can observe all routes transitions and execute (declare) an action in just one place ?
Another way to put put this: If I have a parent route, can I fire the same action to all of its children ?
My current solution is to fire the action on every route's didTransition method like this:
//router.js
Router.map(function() {
this.route('login');
this.route('portal',{ path:'/'}, function() {
this.route('clientes');
this.route('convite');
this.route('usuario', function() {
this.route('view', { path: '/:id' });
});
});
//everyChildren.route.js
didTransition(){
this.super(...arguments);
Ember.$("html, body").animate({ scrollTop: 0 }, "slow");
}
Is there a way to do this ?
PS:. I am using Ember version 2.14.0
You can try to define didTransition action on application route. If child route does not define handler for event, it should bubble up to parent route and application is a most top route.
Alternatively, you can create a mixin with didTransition action, and add that mixin to certain routes.
Also, looking at your code I think you might be interested in using liquid-fire addon (if your goal is animated transitions)
Use ember-router-scroll.
This addon does what you want

EmberJs : How to pass data to a component without using a controller

The documentation for emberjs clearly states that you should not use controllers, however sometimes you need to pass data into a component that is not the model for the corresponding route. For instance in an application I am working on I want to retrieve a list of records from the store and display them in a component so the user can select them as an attribute of the model for that route.
The advice I have received on this is to either create a controller and use it to retrieve the list in question or to add the list of records as an attribute of the model for that route, but since the former is inadvisable and the latter only makes sense if the item in question is a logical part of the model's schema (and therefore should probably be in there anyway) I am left feeling confused about how this apparently simple thing ought to be done. Can anyone help?
You can use Ember.RSVP.hash in your routes model hook. When the promise resolves, the results get passed as the second param in setupController.
// This would be in a route file like app/blogs/edit/route.js
model: function() {
return Ember.RSVP.hash({
blog: this.store.findRecord('blog', 1),
categories: this.store.findAll('category'),
});
},
setupController: function(controller, models) {
this._super(controller, models);
controller.set('model', models.blog);
controller.set('categories', models.categories);
},
OR
If you wanted all the data logic to exist in the component you can inject the data store service. This goes against the DDAU mantra (data down, actions up) but IMO it's a clean, modular solution. Useful if the extra content isn't visible immediately ie: components that open modal windows.
// This would live within the actual component
store: Ember.inject.service(),
loadCategories: function() {
this.get('store').findAll('category').then((categories) => {
this.set('categories', categories);
});
}.on('init'),
However, I would advise against this if the data (categories in this example) were immediately visible in the layout. Ember won't wait for these requests to complete before rendering so you would see blank spaces/whatever with the actual values loading in a half second later.
just be aware that components don't know anything about outside them self. The way I would solve the problem is by creating a bridge between controller and component by passing the property that you want to access to your component.
<script type="text/x-handlebars" data-template-name="sample-com">
{{sample-com
sampleRequests=sampleRequests
}}
</script>
App.MainController = Ember.Controller.extend({
//bridged properties that the controller must communicate between components/view
sampleRequests: 'hello world'
});
App.SampleComComponent = Ember.Component.extend({
sampleRequests: null
});
if there is a better way please feel free to suggest.

Loading several data sources into an Ember UI

I'm trying to understand how to compose a page with multiple data sources and loading spinners in Ember.
Let's you have a UI like this:
http://postimg.org/image/6i1ko340f/
(sorry, don't have reputation to embed image)
And let's say each screen 'module' [books, shows, movies, tweets] has a separate data source at a remote API url.
somesite.com/api/books.json
somesite.com/api/shows.json
somesite.com/api/books.json
twitter.com/api/tweets.json
In order to simplify, and get to the essence of the question, I ask that you don't use:
1) Components
2) A data library (e.g. Ember Model or Ember Data) unless that's essential to the answer.
How would you approach architecting this in Ember so that each module has its own spinner and they load at their own pace (separate route hooks?).
Please help me understand how you would compose your routes, controllers, and models, or whatever else to elegantly solve this extremely common problem. I'll attach some of my approaches and thoughts in the comments :)
Well, I don't know if this is the best way by any means, but this is how I approach that problem. Dummy example using timeouts instead of async calls.
Write some sort of async wrapper. I use ic-ajax wrapper around jQuery ajax to make ajax calls that return promises in a class I call my rest-client. I use initializers to inject this object into all of my routes as restClient as a convenience. You can always just import when you need it.
I would normally block for my model retrieving via Ember.RSVP.hash() calls, but lets assume I did not as you've asked (this is our index route):
import bookModel from 'app/models/book-model';
setupController: function(controller, model){
var self = this;
//do this for each "module" call
this.restClient.get('books/url').then(function(response){
var booksController = this.controllerFor('booksTemplate');
//data is json for the properties of your Book model
var books = model.create(response.data);
booksController.set('isLoading', false);
booksController.set('model', books);
});
}
Make an asynchronous call, and on its success, set the model for the template's controller. Your template books.hbs:
{{#if isLoading}}
<img src="spinner.gif">
{{else}}
{{#each}}
{{this.title}}
{{/each}}
{{/if}}
This template shows a spinner or while loading happens. Notice in the setupController call that we set isLoading to false on complete of the ajax call. This causes the else block to display.
And your books.js controller:
export default Ember.ArrayController.extend({
isLoading: true;
});
And finally, your index.hbs:
{{render 'books'}}
{{render 'otherModel'}}
{{render 'anotherModel'}}
Caveat, if you render the same template twice with a render partial and do not specify the model, the two templates share a singleton instance of the controller meaning isLoading is shared across instances. Holler if you have any questions

Emberjs: how to reach the action of a parentView within an itemsViewClass

Cannot get my head around the following problem. I got a Uncaught TypeError: Cannot read property 'send' of undefined whatever I try. I think it must be the controllerBinding in the itemsViewClass, however I think it is defined correctly.
In the code below there are two showMenu actions. The first one works, but the last one in the itemsViewClass does not.
Please take a look at my code below (I show only the relevant code):
//views/menu.js
import Ember from "ember";
var MenuitemsView = Ember.View.extend({
template: Ember.Handlebars.compile('<div{{action "showMenu" target="view"}}>this works already</div>\
much more code here'),
contentBinding: 'content',
itemsView: Ember.CollectionView.extend({
contentBinding: 'parentView.subCategories',
itemViewClass: Ember.View.extend({
controllerBinding: 'view.parentView.controller', // tried to add controllerBinding but did not help
// this is where the question is all about
template: Ember.Handlebars.compile('<div {{action "showMenu" target="parentView"}}>dummy</div>')
}),
actions: {
showMenu: function(){
// dummy for testing
console.log('showmenu itemsView');
}
}
}),
actions: {
showMenu: function() {
console.log('showMenu parentView!'); // how to reach this action?
}
}
});
export default MenuitemsView;
I have tested with {{action "showMenu" target="view"}} and without a target. It seems not to help.
Do someone have a clue why the second showMenu action cannot be reached?
OK, so this is by no means the only way to do logic separation in Ember, but it's the method I use, and seems to be the method generally used in the examples across the web.
The idea is to think of events and actions as separate logic pools, where an event is some manipulation of the DOM itself, and an action is a translatable function that modifies the underlying logic of the application in some way.
Therefore, the flow would look something like this:
Template -> (User Clicks) -> View[click event] -> (sends action to) -> Controller[handleLogic]
The views and the controllers are only loosely connected (which is why you can't directly access views from controllers), so you would need to bind a controller to a view so that you could access it to perform an action.
I have a jsfiddle which gives you an idea of how to use nested views/controllers in this way:
jsfiddle
If you look at the Javascript for that fiddle, it shows that if you use the view/controller separation, you can specifically target controllers to use their actions, utilising the needs keyword within the controller. This is demonstrated in the LevelTwoEntryController in the fiddle.
At an overview level, what should happen if your bindings are correct, is that you perform an action on the template (either by using a click event handler in the view, or using an {{action}} helper in the template itself, which sends the action to the controller for that template. Which controller that is will depend on how your bindings and routing are set up (i've seen it where I've created a view with a template inside a containerView, but the controller is for the containerView itself, not the child view). If the action is not found within that controller, it will then bubble up to the router itself (not the parent controller), and the router is given a chance to handle the action. If you need to hit a controller action at a different level (such as a parent controller or sibling), you use the needs keyword within the controller (see the fiddle).
I hope i've explained this in an understandable way. The view/controller logic separation and loose coupling confused me for a long time in Ember. What this explaination doesn't do, is explain why you are able to use action handlers in your view, as I didn't even know that was possible :(

ember new router

I have a question about Ember routing and controllers. I've just written a small App to get familiar with the new router. Therefore I've built a button that transitions to another state by clicking on it.
App.PostsView = Em.View.extend({
click: function() {
var router;
this.get('controller').transitionTo('about');
}
});
My question now is: what does the get method return?. Obviously an instance of the PostController but on the one hand the controller doesn't have a transitionTo() method and on the other hand that would not make any sense.
this.get('foo') returns a property of your Ember object. Since Views can have a "controller" property, this.get('controller') returns the controller bound to your view's controller property (by default the postsController).
this.get('controller').transitionTo() works because as sly7_7 mentioned, transitionTo() is also defined on the controller and delegates to the router. Note, it's probably going to be deprecated and one should use
this.get('controller').transitionToRoute('about');
instead.
You should not do this at the view level, this is what the router is designed for so instead of capturing a click event in the view, rather implement an action on the button and let the router handle it. I suggest you learn the best practices from the get-go, chances are your application will evolve, requiring more elaborate concepts such as handling transactions commits/rollbacks, creating/updating records. So here's my suggestion to you
In your view
<button type="button" {{action onSaveClick}} />Save</button>
In your router
App.FooRoute = App.Route.extend({
events: {
onSaveClick: function() {
this.transitionTo('bar');
}
}
})
If for any other reasons, say styling or animation, you find yourself forced to capture the click event in the view, then i suggest to, capture the event, perform your styling and finally send an event to the controller. The event can then be handled the same way in the router
App.FooView = Ember.View.extend({
click: function() {
// Do some styling
this.get('controller').send('onSaveClick')
}
})
Finally speaking of best practices, try to learn when working with ember to think of your application as a series of states interacting with each other. You'll find yourself bound to implement the concept right. Have a look at this
the controller has a transitionTo: https://github.com/emberjs/ember.js/blob/master/packages/ember-routing/lib/ext/controller.js#L36, it basically delegate to it's target (which is the router)