Force a controller to always act as a proxy to a model in Ember - ember.js

I'm looping through a content of an ArrayController whose content is set to a RecordArray. Each record is DS.Model, say Client
{{# each item in controller}}
{{item.balance}}
{{/each}}
balance is a property of the Client model and a call to item.balance will fetch the property from the model directly. I want to apply some formatting to balance to display in a money format. The easy way to do this is to add a computed property, balanceMoney, to the Client object and do the formatting there:
App.Client = DS.Model({
balance: DS.attr('balance'),
balanceMoney: function() {
// format the balance property
return Money.format(this.get('balance');
}.property('balance')
});
This serves well the purpose, the right place for balanceMoney computed property though, is the client controller rather than the client model. I was under the impression that Ember lookup properties in the controller first and then tries to retrieve them in the model if nothing has been found. None of this happen here though, a call to item.balanceMoney will just be ignored and will never reach the controller.
Is it possible to configure somehow a controller to act always as a proxy to the model in all circumstances.
UPDATE - Using the latest version from emberjs master repository you can configure the array controller to resolve records' methods through a controller proxy by overriding the lookupItemController method in the ArrayController. The method should return the name of the controller without the 'controller' suffix i.e. client instead of clientController. Merely setting the itemControllerClass property in the array controller doesn't seem to work for the moment.
lookupItemController: function( object ) {
return 'client';
},

This was recently added to master: https://github.com/emberjs/ember.js/commit/2a75cacc30c8d02acc83094b47ae8a6900c0975b
As of this writing it is not in any released versions. It will mostly likely be part of 1.0.0.pre.3.

If you're only after formatting, another possibility is to make a handlebars helper. You could implement your own {{formatMoney item.balance}} helper, for instance.
For something more general, I made this one to wrap an sprintf implementation (pick one of several out there):
Ember.Handlebars.registerHelper('sprintf', function (/*arbitrary number of arguments*/) {
var options = arguments[arguments.length - 1],
fmtStr = arguments[0],
params = Array.prototype.slice.call(arguments, 1, -1);
for (var i = 0; i < params.length; i++) {
params[i] = this.get(params[i]);
}
return vsprintf(fmtStr, params);
});
And then you can do {{sprintf "$%.2f" item.balance}}.
However, the solution #luke-melia gave will be far more flexible--for example letting you calculate a balance in the controller, as opposed to simply formatting a single value.
EDIT:
A caveat I should have mentioned because it's not obvious: the above solution does not create a bound handlebars helper, so changes to the underlying model value won't be reflected. There's supposed to be a registerBoundHelper already committed to Ember.js which would fix this, but that too is not released yet.

Related

Emberjs: Use args as tracked property

I am doing a store query in the controller and then passing the result down to a child component.
// Controller
#tracked comment;
#action
async fetchComment() {
const comment = await this.store.query('note', {
filter: {
listing: this.listing.id,
},
});
if (comment && comment.length > 0) {
this.comment = comment.firstObject;
}
}
// Template
<MyComponent #comment={{this.comment}} />
I want to use the arg to populate a tracked property in the child component.
// Component
#tracked comment = this.args.comment;
I found this does not work but works well as a getter. However with a getter I am unable to set this to null when deleting that record.
I have also tried to set the tracked property in the Constructor but that didnt work either.
I suspect this has something to do with passing in a promise or store object in the args because this works fine with static data.
why your code does not work
this code can not work:
#tracked comment = this.args.comment;
this is because comment on the controller is initially undefined but will later bet set to comment.firstObject when the network request is done and the await in your fetchComment function returns.
Generally everythings on args basically always behaves like its #tracked (while more accurate you would describe it as getters). So this usually will just update fine. But the assignment #tracked comment = this.args.comment; only happens once when you create the component, so you no longer depend on updates on args.
why you can not set this.args.comment to null
If you use a getter or directly always use this.args.comment you can not change this reference. This is because this.args is always readonly. you can change objects on this.args.something, but you never can change the reference or primitive value on this.args.
Sidenote: this is only true if the component was called with <AngleBracket /> syntax. For the older {{curly-component}} syntax this is not true. So this does not depend on the component itself but how the component gets called.
you could notify the controller to remove the reference
one good thing to do is to pass down a deleteComment action to the component that basically does something like this.comment = null on the controller. then you use this.args.comment directly or by a getter and you can call this.args.deleteComment() to set comment on the controller to null, which will update anything that uses this.args.comment or a getter that returns this.args.comment.
this is essentially because in your architecture the controller owns the data (because it loads it). so the controller is also responsible to delete it.
if you use ember-data you can check isDeleted
if its a ember-data model (which it probably is if you call this.store) then it has a isDeleted property. you can use this to check if the record is deleted, since ember-data records dont disappear if they get deleted. which is exactly because of problems like this.
how you use another property to shadow a argument
you could do something like this to shadow an argument in your component:
#tracked commentIsDeleted = false;
get comment() {
return this.commentIsDeleted
? null
: this.args.comment;
}
this way at first this.comment will work like a normal getter, but you can shadow delete it by setting this.commentIsDeleted = true;. From that on this.comment will be null.

How to maintain unknown/wildcard queryParams through a transition?

I have a route (route-a) that transitions to another route (route-b) and I am trying to find a way for the destination URL to maintain the all query parameters, even if route-b does not know about them in advance.
For example, if a user visits https://example.com/route-a/?var1=x&var2=y, and the transition to route-b happens like this:
afterModel(model, transition) {
this.transitionTo('route-b', model, {queryParams: transition.to.queryParams}) // transition route-a to route-b
}
...the ultimate URL will be https://example.com/route-b/ — without the query params.
Now, I realize the "Ember way" is to define the queryParams on route-b's controller in advance, but in this particular use-case, I do not know the queryParams in advance. Route B consumes any and all query params provided to it, which means they would be impossible to enumerate in advance.
How can I transition to a new route without dropping query parameters that are not specifically enumerated on the destination route's controller?
Is there a way to handle unknown queryParams, or is there the notion of a wildcard for queryParams (similar to *path routes)?
Update: I'm not marking this as the answer, because as jelhan notes below, using a computed property for this key is explicitly identified as a no-no in the docs. But it worked for our use-case, and it might for others, though I'm guessing it may break down if you have additional queryParams in other routes that might conflict when Ember attempts to combine them.
Previous answer:
My solution here ended up using Ember's computed method to auto-generate the Array of query params by parsing the URL.
queryParams: computed("router.location", function () {
let qp = this.get("router.location").getURL().split("?")[1];
if (qp) {
let qpAsObj = JSON.parse(
'{"' +
decodeURI(qp)
.replace(/"/g, '\\"')
.replace(/&/g, '","')
.replace(/=/g, '":"') +
'"}'
);
return Object.keys(qpAsObj)
}
})
If you don't want to subsequently maintain those query params on the page/model the next time a user re-visits that page ("sticky query params"), you will also need to remove the queryParams on the route:
resetController(controller) {
// unset all queryParams when leaving the route
controller.queryParams.forEach(v => {
controller.set(v, null)
})
}
This solution is... not ideal, but it works and we have tests written to ensure that we will catch any errors if it breaks going forward.

How to pass a #tracked object from an Ember route model hook

My question is two-fold:
Where is the best place to put some kind of polling logic - in the route file right?
How do I pass this constantly updating value from the Route to some child component? Labeling some variable as "#tracked" and then passing the tracked variable via the model hook?
Let's say I have something like this:
routes/index.js
export default class IndexRoute extends Route {
#tracked
recent: {
A: 0,
...
},
constructor() {
super(...arguments);
this.getRecent();
}
getRecent() {
// poll data / fetch latest
const {A, ...partialObject} = this.recent;
this.recent = { ...partialObject, A: <some new value fetched>};;
later(this, this.getRecent, 2000);
}
model() {
return this.recent;
}
}
application.hbs
<p>constantly updating "this.recent": {{ this.model.A }} </p>
I thought if I use the model hook like this, it would be tracked and therefore auto-update but that was not the case. I have this sample Ember Twiddle that emulates what I'm trying to do. I tried to force a re-compute by reassigning the entire variable but it didn't work.
This question is a deeper dive from my initial question here.
You are returning a reference to object stored in this.recent in your model hook. But the getRecent method does not change that object but overrides this.recent. After the first execution of getRecent method the model of the route and this.recent aren't the same object anymore. The model of the route, which you can access through this.modelFor(this.routeName) is the initial value and this.recent is the new value.
You want to mutate the object returned from model hook instead.
The object given in your example has a fixed schema. This allows you to mark the property A as tracked:
recent: {
#tracked A: 0,
...
}
As currently you return the value of this.recent in your model hook. But instead of overwriting it in getRecent method, you are only changing the value of it's property A:
getRecent() {
this.recent.A = <some new value fetched>;
later(this, this.getRecent, 2000);
}
If you don't know the schema of the object returned in model hook or if you are dealing with an array, it's a little bit more complicated. You wouldn't have a property to decorate with #tracked. I would recommend to use the tracked-built-ins package in that case.
For arrays you can also fallback to legacy MutableArray from #ember/array/mutable package. But you must make sure in that case that you use it's custom methods to manipulate the array (e.g. pushObject instead of push).

computed.oneWay not working with Ember Data

I have an EmberData snapshot which I'd like decorate with a few additional attributes before handing over to the UI for presentation. This decoration will be setting "properties" of the Ember-Data record not actual attributes. It looks like this:
let foo = Ember.computed.oneWay(this.get('store').find('activity'));
foo.map(item => {
item.set('foobar', 'baz');
return item;
}
I would then hope that foo would be the beneficiary of the promised record (it is) and the setting of the foobar property would be localized to the foo property (it's not, it seems to be globally scoped to the record's properties).
As for me this is expected behavior.
1) OneWay means only you are not bind set method on foo. It used to work between properties of objects, but this.get('store').find('activity') is a just promise.
2) foo is store.find() result of DS.RecordArray type (assuming promise is resolved). So you are iterating on records returned and set foobar property on them.
Achieving your goal, you could decorate activity record by component (Ember 2.0 way) for UI presentation.
So far the only way I've been able to do this is using Ember's ObjectProxy like so:
const FooDecorator = Ember.ObjectProxy.extend({
foobar: 'baz'
});
let foo = Ember.computed(function() {
return this.get('store').find('activity').map(item => {
FooDecorator.create({content: item});
});
}
This works but I thought I'd been hearing things about Object proxies not being a welcome part of Ember 2.0 roadmap so not sure if this approach is best. I'll keep this open for a few days before closing.

Adding item to filtered result from ember-data

I have a DS.Store which uses the DS.RESTAdapter and a ChatMessage object defined as such:
App.ChatMessage = DS.Model.extend({
contents: DS.attr('string'),
roomId: DS.attr('string')
});
Note that a chat message exists in a room (not shown for simplicity), so in my chat messages controller (which extends Ember.ArrayController) I only want to load messages for the room the user is currently in:
loadMessages: function(){
var room_id = App.getPath("current_room.id");
this.set("content", App.store.find(App.ChatMessage, {room_id: room_id});
}
This sets the content to a DS.AdapterPopulatedModelArray and my view happily displays all the returned chat messages in an {{#each}} block.
Now it comes to adding a new message, I have the following in the same controller:
postMessage: function(contents) {
var room_id = App.getPath("current_room.id");
App.store.createRecord(App.ChatMessage, {
contents: contents,
room_id: room_id
});
App.store.commit();
}
This initiates an ajax request to save the message on the server, all good so far, but it doesn't update the view. This pretty much makes sense as it's a filtered result and if I remove the room_id filter on App.store.find then it updates as expected.
Trying this.pushObject(message) with the message record returned from App.store.createRecord raises an error.
How do I manually add the item to the results? There doesn't seem to be a way as far as I can tell as both DS.AdapterPopulatedModelArray and DS.FilteredModelArray are immutable.
so couple of thoughts:
(reference: https://github.com/emberjs/data/issues/190)
how to listen for new records in the datastore
a normal Model.find()/findQuery() will return you an AdapterPopulatedModelArray, but that array will stand on its own... it wont know that anything new has been loaded into the database
a Model.find() with no params (or store.findAll()) will return you ALL records a FilteredModelArray, and ember-data will "register" it into a list, and any new records loaded into the database will be added to this array.
calling Model.filter(func) will give you back a FilteredModelArray, which is also registered with the store... and any new records in the store will cause ember-data to "updateModelArrays", meaning it will call your filter function with the new record, and if you return true, then it will stick it into your existing array.
SO WHAT I ENDED UP DOING: was immediately after creating the store, I call store.findAll(), which gives me back an array of all models for a type... and I attach that to the store... then anywhere else in the code, I can addArrayObservers to those lists.. something like:
App.MyModel = DS.Model.extend()
App.store = DS.Store.create()
App.store.allMyModels = App.store.findAll(App.MyModel)
//some other place in the app... a list controller perhaps
App.store.allMyModels.addArrayObserver({
arrayWillChange: function(arr, start, removeCount, addCount) {}
arrayDidChange: function(arr, start, removeCount, addCount) {}
})
how to push a model into one of those "immutable" arrays:
First to note: all Ember-Data Model instances (records) have a clientId property... which is a unique integer that identifies the model in the datastore cache whether or not it has a real server-id yet (example: right after doing a Model.createRecord).
so the AdapterPopulatedModelArray itself has a "content" property... which is an array of these clientId's... and when you iterate over the AdapterPopulatedModelArray, the iterator loops over these clientId's and hands you back the full model instances (records) that map to each clientId.
SO WHAT I HAVE DONE
(this doesn't mean it's "right"!) is to watch those findAll arrays, and push new clientId's into the content property of the AdapterPopulatedModelArray... SOMETHING LIKE:
arrayDidChange:function(arr, start, removeCount, addCount){
if (addCount == 0) {return;} //only care about adds right now... not removes...
arr.slice(start, start+addCount).forEach(function(item) {
//push clientId of this item into AdapterPopulatedModelArray content list
self.getPath('list.content').pushObject(item.get('clientId'));
});
}
what I can say is: "its working for me" :) will it break on the next ember-data update? totally possible
For those still struggling with this, you can get yourself a dynamic DS.FilteredArray instead of a static DS.AdapterPopulatedRecordArray by using the store.filter method. It takes 3 parameters: type, query and finally a filter callback.
loadMessages: function() {
var self = this,
room_id = App.getPath('current_room.id');
this.store.filter(App.ChatMessage, {room_id: room_id}, function (msg) {
return msg.get('roomId') === room_id;
})
// set content only after promise has resolved
.then(function (messages) {
self.set('content', messages);
});
}
You could also do this in the model hook without the extra clutter, because the model hook will accept a promise directly:
model: function() {
var self = this,
room_id = App.getPath("current_room.id");
return this.store.filter(App.ChatMessage, {room_id: room_id}, function (msg) {
return msg.get('roomId') === room_id;
});
}
My reading of the source (DS.Store.find) shows that what you'd actually be receiving in this instance is an AdapterPopulatedModelArray. A FilteredModelArray would auto-update as you create records. There are passing tests for this behaviour.
As of ember.data 1.13 store.filter was marked for removal, see the following ember blog post.
The feature was made available as a mixin. The GitHub page contains the following note
We recommend that you refactor away from using this addon. Below is a short guide for the three filter use scenarios and how to best refactor each.
Why? Simply put, it's far more performant (and not a memory leak) for you to manage filtering yourself via a specialized computed property tailored specifically for your needs