I'm writing an Ember.js app to show a list of nested comments fetched from a CRUD RESTful API.
Half way through, I realize I'm probably misusing Ember.js and not taking advantage of its paradigms.
For instance, my Comment object looks like this:
App.Comment = Em.Object.extend({
id: null,
author: null,
text: null,
delete: function() { /* AJAX call to API here */ }
});
Is it alright to ha the delete() function as part of the model object, instead of a controller?
Another doubt I have is in my handling of states. In my template I do something like this:
{{#if view.comment.editing}}
{{view Ember.TextArea valueBinding="view.comment.text"}}
<a href="#" {{action cancelEditingComment}}>Cancel</a>
{{else}}
<p>{{view.comment.text}}</p>
<a href="#" {{action editComment}}>Edit</a>
{{/if}}
Then in my router, the editComment and cancelEditingComment actions will delegate to Comment, which has functions:
startEditing: function() { this.set('editing', true); }
cancelEditing: function() { this.set('editing', false); }
I can't help but think that I'm doing something wrong, although this kind of code seems to work.
Do you have any suggestions about how to reorganize my code, and any recommended reading that might help me with this?
From my experiences, your model shouldn't really have any business logic in it. It should just have a set of fields and maybe some computed properties if you have some complex fields that can be generated.
Your view delegating to your controller is definitely the right move for deleting. When it comes to editing though, seeing as it's only really your view that cares about this (typically), I'd be inclined to make isEditing part of the view itself. Then you can check this flag to decide whether to draw simple text or a textarea for input.
App.controller = Em.Object.create({
comments: [],
deleteComment: function(comment) {
this.get('comments').removeObject(comment);
}
});
App.CommentView = Em.View.extend({
comment: null,
isEditing: null,
delete: function() {
App.controller.deleteComment(this.get('comment'));
},
startEditing: function() {
this.set('isEditing', true);
}
});
Related
I'm attempting to implement form validation on a new Contact in my app using the ember-validations library. I'm currently using Ember Data with fixtures, and I've opted to place the validations in the model like the example in this video. I've been grappling with this for days now, and still can't seem to figure out why the validations aren't working. I'm not getting any indication that errors are even firing.
//app/models/contact.js
import DS from "ember-data";
import EmberValidations from 'ember-validations';
//define the Contact model
var Contact = DS.Model.extend(EmberValidations, {
firstName: DS.attr('string'),
lastName: DS.attr('string'),
});
//Create Contact fixtures
Contact.reopenClass({
FIXTURES: [...]
});
Contact.reopen({
validations: {
firstName: {
presence: true,
length: { minimum: 2 }
},
lastName: {
presence: true
}
}
});
export default Contact;
I'm new to Ember, and have been advised to put the following logic in routes instead of the controller. I haven't seen any examples of this being done with ember-validations, so I'm unsure if that's my issue regarding validations.
app/routes/contacts/new.js
import Ember from 'ember';
export default Ember.Route.extend({
model: function() {
return this.store.createRecord('contact');
},
actions: {
createContact: function() {
var contact = this.get('currentModel');
this.transitionTo('contacts');
contact.save();
alert(contact.errors);
},
cancelContact: function() {
var contact = this.get('currentModel');
contact.destroyRecord();
this.transitionTo('contacts');
}
}
});
My other suspicion is that I may not be handling the errors in html correctly?
//app/templates/contacts/new.hbs
{{#link-to 'contacts' class="btn btn-primary"}}Contacts{{/link-to}}
<form>
<label>First Name:</label>
{{input type="text" value=model.firstName}}<br>
<span class="error"></span>
<label>Last Name:</label>
{{input type="text" value=model.lastName}}<br>
<span class="error"></span>
</form>
<button {{action "createContact"}} class="btn btn-primary">Submit</button>
<button {{action "cancelContact"}} class="btn btn-warning">Cancel</button>
<br>
Here is my controller
//app/controllers/contacts.js
import Ember from "ember";
export default Ember.Controller.extend({
});
I'm enjoying Ember, but this issue is stonewalling me greatly. Any help would be much appreciated.
I'm going through this exact thing and have some advice. First I would say validate where you need to ask something if it is valid. You might need to do this on the component if it's a form, you might need to do this on a model if you want to ensure it's valid before saving, or maybe on a route if there are properties there that you're wanting to check.
In any case whatever method you pick, I would highly recommend using the ember-cp-validations addon. For what it's worth, Stephen Penner (ember.js core team) has contributed to the addon, too. It's all ready for Ember CLI as well.
The setup is actually very similar to what you're doing, but instead of reopening the class, you would define with it a mixin (example from their docs). To create the mixin that's used they have a factory called buildValidations. The nice thing is that you can use this on any Ember object.
Once you've defined your validation and mixed it into the create of your object, ie: Ember.Object.create(Validations, {}); where Validations is the mixin you've created just above (like in the docs). You are all set.
Within scope of that object you now have a validations property on the object, so something like:
var Validations = buildValidations({
greeting: validator('presence', true)
});
export default Ember.Object.create(Validations, {
greeting: 'Hello World',
actions: {
announce: function() {
alert('The current validation is: ' + this.get('validations.isValid'));
// per property validation is at:
alert('The individual validation is: ' + this.get('validations.attrs.greeting.isValid'));
}
}
})
Handlebars:
Looks like the form is {{ validations.isValid }}.
You can also <a {{action announce}}>announce the validation</a>.
Also, take a look at all the docs, there are is even more properties and use cases that this addon takes care of, including handlebars helpers, ajax/async resolution of validation, and some validators to use. If you don't find the one you're after make a function validator. Using the function validator all over, easy, make it re-usable with ember generate validator unique-username.
Hope this gets you off in the right start. This is a relatively new project but has decent support and responses on the issues has been quick.
Should also mention that because these validations are based on computed properties they work in an "Ember way" that should work great, including your models.
Im struggling to delete a view's instance. On view hbs i use each loop to show view hbs. On another field click i add a " . " to a json object, which then adds another field to the template.
>js>App.ApplicationView = Ember.View.extend({
anotherField: [{name: 'testname'}],
actions: {
moreFields: function(){
this.get('anotherField').pushObject({name: ''});
},
less: function(){
var counter = this.get('anotherField');
counter.shift();
this.set('anotherField', counter);
And hbs
{{#each view.anotherField}}
{{view Ember.TextField}}
{{/each}}
<button {{action 'moreFields' target='view'}}> ++ </button>
<button {{action 'less' target='view'}}> -- </button>
http://jsbin.com/iSUdiCaX/17/edit
Cheers
Kristjan
When you use the shift method Ember doesn't get notified that the anotherField property changed, and therefore it doesn't update the template. You can check this by adding this.rerender() at the end of the less action.
You could:
call this.propertyDidChange('anotherField') to notify the property changed: http://emberjs.com/api/classes/Ember.Object.html#method_propertyDidChange
use the slice method: http://emberjs.com/api/classes/Ember.Array.html#method_slice
var sliced = this.get('anotherField').slice(0, this.get('anotherField').length - 1);
this.set('anotherField' sliced);
I also noticed you're using the View to handle the actions whereas I believe the Controller would be a better place to do so.
EDIT
Well it depends.... I believe the controllers are a good place because they have knowledge of the model (the view also has it via the controller). if your anotherField property is only needed for displaying or event handling logic then I believe it is a good idea to leave it in the view. from docs
Views in Ember.js are typically only created for the following
reasons:
When you need sophisticated handling of user events
When you want to create a re-usable component
But if instead the anotherField property is used the held application state (user selections, needed for computed properties or other actions) then I believe it's better placed inside the controller (and therefore the actions modifying it).
Have in mind your view can handle one part of the action and send it to the controller:
actions: {
something: function() {
.....
this.get('controller').send('something') // calls send action in controller
}
}
I hope this helps!
I have a small extract from my Ember app here. My page contains a number of views each containing different data each with their own controllers.
I want a search field (in index view) to go in one view which should "talk" to the stationList controller to update the content of the stationList view. This doesn't work. I get an error: TypeError: this.get(...).search is not a function
The logging outputs the name of the contoller I've asked it to use: App.StationListController
I added a second search form inside on the StationList View. This one works just fine. The logging this time outputs a dump of the StationListController object. So I am guessing that the other search form, despite my code (in SearchFormView): controllerBinding : 'App.StationListController', is not correctly setting the controller.
So I guess my question is why not?
How can I route the change on the form field in the one view to call a funciton on another view's controller?
Here's my code:
<script type="text/x-handlebars" data-template-name="application">
{{outlet}}
</script>
<script type="text/x-handlebars" data-template-name="index">
<div id="searchForm">search form view search:
{{#view App.SearchFormView}}
{{view App.StationSearchField}}
{{/view}}
</div>
<div id="stationList">{{render stationList}}</div>
</script>
<script type="text/x-handlebars" data-template-name="stationList">
station list view search: {{view App.StationSearchField}}
<ul>
<li>List</li>
<li>will</li>
<li>go</li>
<li>here</li>
</ul>
{{searchTerm}}
</script>
And
App = Ember.Application.create({})
App.SearchFormView = Ember.View.extend({
init : function()
{
console.log("SearchFormView init", this.get('controller'))
}
})
App.StationSearchField = Ember.TextField.extend({
keyUp: function(event) {
var searchTerm = this.value
console.log("value",searchTerm,this.get('controller'))
this.get('controller').search(searchTerm)
}
})
App.StationListController = Ember.ArrayController.extend({
content : [],
searchTerm : null,
search : function(term)
{
this.set("searchTerm",term)
console.log("searching",term)
}
});
Fiddle: http://jsfiddle.net/ianbale/8QbrK/14/
I think the controllerBinding stuff is from the older version, I don't think that works anymore.
You can use controllerFor on get('controller') in the StationSearchField.
this.get('controller').controllerFor('station_list').search(searchTerm)
But controllerFor is deprecated and may be removed. Depending on your application structure you use needs on the controller.
Another way which I am using, is to send a custom event from the View, which the Route then sends to the corresponding controller.
App.IndexRoute = Ember.Route.extend({
events: {
search: function(term) {
controller = this.controllerFor('station_list')
controller.search(term);
}
}
});
and dispatch a search event from view like so.
this.get('controller').send('search', searchTerm);
The advantage of this method is you dispatch the same event from multiple places and it would get handled in the same way.
Here's the updated jsfiddle.
I'm trying to create a directive that would enhance an HTML element. So I managed to get the directive to run and to be associated with the element My current code is something like this:
angular.module('myModule', [])
.directive('myDirective', function() {
return {
restrict: 'C',
replace: false,
scope: {},
link: function(scope, element, attrs) {
}
}
});
Now I would like to add new methods to the HTML element, for example I would like to do this:
// Pseudo code
myElement.reset();
myElement.reload(); // etc.
What would be the best way to add these methods to the directive?
Adding new methods to elements is not the Angular way. The angular way would be creating object with fields, passing it to directive and watch for field changes inside directive. Here is simple example: http://plnkr.co/edit/5v5mN69Bu18jpnoGwYqj?p=preview
Your example of your directive is very basic, so I can't see what do you want to achieve.
At least I can say: You can define new functions as functions of the scope , e.g.
...
link: function(scope, element, attrs) {
scope.reset = function() {
// reset something
}
// ...
}
If you want to access data loaded (e.g. for use in function reload()) in the scope you should write a controller for this use. so you can inject a service as a data source.
Implementing functions bound to elements directly is more the jQuery way to do not the angularjs one. In angularjs you work with scopes mainly.
Maybe you provide a more complete example at best using jsfiddle or plnkr, I think it easier to help to see your use case or your problem as a piece of working code.
One way to add these methods to your directive is to make the directive a controller (aka a subview). The $scope param in the controller will give you bi-directional access to the HTML in the template:
For example:
.directive("myDirective", function() {
var controller = ['$scope', function teamCountCtrl ($scope)
{
$scope.reset = function() {
// modify $scope.obj
};
$scope.reload = function() {
// modify $scope.obj
};
}];
return {
replace: true,
templateUrl: 'js/directives/teamCount.html',
scope: {
obj: '='
},
controller: controller
}});
Then in the template HTML you can call reset() or reload():
<div>
<a tabindex=-1 class="btn" href="#" ng-click="reset()">
<i class="fa fa-fw"></i>
</a>
<a tabindex=-1 class="btn" href="#" ng-click="reload()">
<i class="fa fa-fw"></i>
</a>
First off I want to say that I really like ember.js. I have tried both Knockout and Angular but found them a bit to obtrusive and everything had to be done their way. I feel like ember allows me a bit more freedom to structure things how you see fit. With that said I have a couple of questions.
1. I would like to do something like the following which obviously doesn't work:
<h3>{{ content.name }}</h3>
Instead I would have to create a binding:
<a {{ bindAttr href="url" }}><h3>{{ content.name }}</h3></a>
How do i create the url path in the view? I could easily create a computed property called url on the model but that feels horrible and not very MVC. Do I have to create a new view for the element or register a helper which feels a bit cumbersome?
Here's the complete code:
App = Ember.Application.create();
var sampleData = [ Ember.Object.create({ id: '123456789', name: 'John' }), Ember.Object.create({ id: '987654321', name: 'Anne' }) ]
App.itemController = Ember.ArrayController.create({
content: sampleData,
removeItem: function(item) {
this.content.removeObject(item);
}
});
App.ItemListView = Ember.View.extend({
itemDetailView: Ember.CollectionView.extend({
contentBinding: 'App.itemController',
itemViewClass: Ember.View.extend({
tagName: 'li',
url: '' // HOW TO GET '/item/123456789'
deleteButton: Ember.Button.extend({
click: function(event) {
var item = this.get('content');
App.itemController.removeItem(item);
}
})
})
})
});
<script type="text/x-handlebars">
{{#view App.ItemListView}}
<ul id="item-list">
{{#collection itemDetailView}}
<div class="item">
<a {{ bindAttr href="url" }}><h3>{{ content.name }}</h3></a>
{{#view deleteButton class="btn" contentBinding="content"}}Delete{{/view}}
</div>
{{/collection}}
</ul>
{{/view}}
</script>
2. I feel that the view "owns" the controller and not the other way around. Shouldn't the view be unaware of which controller it is hooked up to so you can reuse the view? I'm thinking about these to lines in the view:
contentBinding: 'App.itemController',
and
App.itemController.removeItem(item);
How do you structure this?
3. I realize everything is a work in progress and quite new with the name change and all but the documentation is quite unclear. The examples use the old namespace SC and there are lot of things missing on emberjs.com compared to the Sproutcore 2.0 guides, for example collections, arraycontrollers. I read somewhere here that collections will be phased out. Is that true and should I use #each instead?
Thanks for your help and for an awesome framework!
1.) If you want to use <a href="...">, you will need a computed property. It could be on your model or on a view. Another technique would be to use Ember.Button: {{#view Ember.Button tagName="a" target="..." action="..."}}...{{/view}}
2.) Typically you'll want to declare your controller binding in the template, rather than in the view. For example: {{#view App.ItemListView contentBinding="App.itemController"}}
3.) The #collection helper will likely be deprecated, so you should probably use an #each instead.