I am building a subscriber/observer pattern for displaying data in realtime for my angular app.
The observer is built with a factory injected into the angular controller and whose role is to fetch data and update it. The basic code structure can he found in this fiddle: http://jsfiddle.net/ctrager/67QR7/3/
var myApp = angular.module('myApp', [])
.factory('MyFactory', [function () {
var Collection = {};
Collection.isLoaded = 0;
Collection.data = [1, 2];
Collection.username = "corey and eric";
Collection.update = function () {
Collection.data.push(new Date())
}
Collection.replace = function () {
// If you do Collection.data = []
// here you are doing the same thing
// as the empty collection bug. I can't
// tell you EXACTLY why this confuses angular
// but I'm 99% sure it's the same phenomenon
Collection.data = [new Date()]
}
Collection.replace_fixed = function () {
// This works
Collection.data.length = 0
Collection.data.push(new Date())
}
return Collection;
}])
function MyCtrl($scope, MyFactory) {
$scope.name = 'Eric';
$scope.items = MyFactory.data;
$scope.replace = function(){
console.log("replace")
MyFactory.replace()
//$scope.items = MyFactor.data;
}
$scope.replace_fixed = function(){
console.log("replace_fixed")
MyFactory.replace_fixed()
//$scope.items = MyFactor.data;
}
$scope.update = function(){
console.log("update")
MyFactory.update()
}
}
The factory (MyFactory) contains a collection (Collection.data). Any push (/splice) to that collection is reflected in the scope, but if I replace the entire collection (Collection.replace()) the change is no longer reflected in $scope. Any idea why?
This works:
http://jsfiddle.net/67QR7/4/
changed the thing stored on scope to be the factory instead of data. then the html repeat to do items.data.
So it looks like this is because you replaced the reference inside collection, but that doesn't change where $scope.items was pointing to.
So you are creating a reference to MyFactory.data from $scope.items. Angular puts a $watch on $scope.items and looks for changes. When you call MyFactory.replace, you change MyFactory.data, but $scope.items remains the same. So as far as your watch is concerned, nothing has happened.
You can fix this by using replace_fixed, or watch for changes to MyFactory.data. http://jsfiddle.net/KtB93/
$scope.MyFactory = MyFactory;
$scope.$watch("MyFactory.data", function(newData) {
console.log('myFactory.data changed');
$scope.items = newData;
});
Or alternatively (probably better), you can use a function as the watch expression so you don't have to plop MyFactory on the scope (http://jsfiddle.net/XAW54/1/):
$scope.$watch(function() {
return MyFactory.data;
}, function(newData) {
$scope.items = newData;
});
Related
I have one service for handling data, and one for logic.
app.service('DataService', function() {
this.stuff = [false];
this.setStuff = function(s){
this.stuff = angular.copy(s);
}
});
The data service has a set function and a data property.
app.service('LogicService', function(DataService, $http) {
DataService.setStuff(["apple", "banana"]);
$http.get("./data.json").then(function(res){
DataService.setStuff(res.data.stuff);
});
});
I am assigning a property of the data service to the controller for binding to the DOM.
app.controller('MainCtrl', function($scope, DataService, LogicService ) {
$scope.message = "Hello, World!";
$scope.stuff = DataService.stuff;
//This is the only way I could get it to work, but isn't this JANKY?
//$scope.$watch(
// function(){
// return DataService.stuff
// },
// function(n,o){
// $scope.stuff = n;
// })
})
If I 'seed' the data service when the logic service is instantiated, and then later update it following an $http call, the DOM reflects the 'seeded' or initial value, but does not update.
Is there something fundamental I am missing in my understanding of the digest loop?
If I add a $watch function in my controller, all is well, but this seems yucky.
//FIXED//
#scott-schwalbe 's method of using Object.asign() works nicely, preserves my original structure, and is one line.
this.setStuff = function(s){
Object.assign(this.stuff, s);
}
Working Plunker
(sorry for titlegore)
If your data property is an object and is binded to the scope, then the scope will update whenever the object changes as long as you don't dereference it (eg data = x). Are you reassigning data object on the $http call?
An alternative to your current code to keep the reference using Object.assign
app.service('DataService', function() {
this.stuff = [false];
this.setStuff = function(s){
Object.assign(this.stuff, s);
}
});
var app = angular.module('plunker', []);
app.controller('MainCtrl', function($scope, DataService) {
$scope.message = "Hello, World!";
//Get stuff data from your service, this way you stuff lives in your service
//And can be accessed everywhere in your app.
//It also makes your controller thin. Which is the top priority
$scope.stuff = DataService.getStuff();
//Or async
DataService.getStuffAsync()
.then(function(val){
$scope.asycStuff = val;
});
this.clickFromAButton = function(){
DataService.setStuff(["apple", "banana"]);
};
});
app.service('DataService', function() {
this.stuff = [false];
this.asyncStuff;
this.setStuff = function(s){
this.stuff = angular.copy(s);
};
this.getStuff = function(){
return this.stuff;
};
this.getStuffAsync = function(){
//If i already fetched the data from $http, get it from the service.
return this.asyncStuff || $http.get("./data.json").then(function(res){
//When i fetch it for the first time I set the data in my service
this.asyncStuff = res.data;
//and I return the data
return res.data;
});
};
});
This is a good 'pattern' to follow ;)
Instead of putting "stuff" on scope. Put your DataService object on scope.
app.controller('MainCtrl', function($scope, DataService, LogicService ) {
$scope.message = "Hello, World!";
$scope.DataService = DataService;
//$scope.stuff = DataService.stuff;
HTML
<body ng-controller="MainCtrl">
{{DataService.stuff}}
</body>
The $interpolate service will automatically places a $watch on DataService.stuff. Thus there is no need to do it inside your controller.
The DEMO on PLNKR.
This is my controller:
app.controller("PlaceController", ['$http', function($http){
this.places = shops;
var hotels = this;
hotels.objects = [];
this.spots = new Array;
this.newPlace = {};
this.city = new String();
this.addPlace = function() {
this.places.push(this.newPlace);
this.newPlace = {};
var request = *some query syntax, sorry for hiding*
$http.get(request).success(function(data) {
hotels.objects = data;
console.log(hotels.objects.elements);
});
for (each in hotels.objects.elements) {
this.spots.push(each.tags.name);
};
console.log(this.spots);
}}] );
I get an empty array when I log this.spots to the console. The http request etc work perfectly because the console.log(hotels.objects.elements) statement works perfectly.
Because of this problem, I can't output it into my HTML either. What should I do?
You are issuing an asynchronous request to get the spots, but you're logging them before they complete.
Change this.addPlace to log / act on the spots array inside the promise callback:
this.addPlace = function() {
this.places.push(this.newPlace);
this.newPlace = {};
var request = *some query syntax, sorry for hiding*
$http.get(request).success(function(data) {
hotels.objects = data;
console.log(hotels.objects.elements);
for (each in hotels.objects.elements) {
this.spots.push(each.tags.name);
};
console.log(this.spots);
});
You're adding to the spots array before the ajax request is done, move your calls to push inside the callback:
$http.get(request).success(function(data) {
hotels.objects = data;
console.log(hotels.objects.elements);
angular.forEach(hotels.objects.elements, function(value) {
hotels.spots.push(value.tags.name);
});
});
Also, you should really be using $scope instead of references to this. This would simplify your code a bit, without needing to rename this to hotels
full controller code using $scope
app.controller("PlaceController", ['$scope', '$http', function($scope, $http){
$scope.places = shops;
$scope.objects = [];
$scope.spots = new Array;
$scope.newPlace = {};
$scope.city = new String();
$scope.addPlace = function() {
$scope.places.push($scope.newPlace);
$scope.newPlace = {};
var request = *some query syntax, sorry for hiding*
$http.get(request).success(function(data) {
$scope.objects = data;
console.log($scope.objects.elements);
angular.forEach($scope.objects.elements, function(value, key) {
$scope.spots.push(value.tags.name);
});
// spots is ready, log it, do whatever
console.log($scope.spots);
});
}}] );
NOTE: Using $scope means you won't need to call this from your html to reference the objects and functions defined in your controller.
An example:
<div ng-controller="PlaceController">
<!-- no need to call places.city, if you use $scope just write city -->
{{city}}
</div>
EDIT: You probably shouldn't use JavaScript's for-in, the problem with it is that it iterates on the names or indexes of your objects/arrays.
An example:
var someArray = ['a', 'b', 'c'];
for (i in someArray) {
console.log(i); // prints 0, 1, 2
console.log(someArray[i]); // prints 'a', 'b', 'c'
}
This is different from any for-in/for-each implementation in other popular languages.
Anyway, in this case I've edited the code above to use Angular's forEach, which is a more appropriate solution (many libraries implement custom for-each functions to fix JS's weird for-in)
You can read more in Angular's docs
Another option, in plain javascript is, if $scope.objects.elements is an array, using the map() function, like this:
$scope.spots = $scope.objects.elements.map(function(value) {
return value.tags.name; // value is an item in object.elements
});
try this ..
due to your async call you need to perform task inside success
$http.get(request).success(function(data) {
hotels.objects = data;
console.log(hotels.objects.elements);
for (each in hotels.objects.elements) {
hotels.spots.push(each.tags.name);
};
console.log(this.spots);
});
Hope, my question itself, conveys what I am look for.
Will put the words in detail
1. Created the Module.
var ang = angular.module('myApp', []);
I have a controller called controller1, and includes the 'campaign' factory.
//controllerone.js
ang.controller('controller1', function(campaign){
$scope.campaigns = new campaign();
//Here the whole campaign object is displayed with data, refer the Image 1 attached
console.log($scope.campaigns);
});
ang.factory('campaign', function($http){
var campaign = function(){
this.timePeriodList = buildTimePeriodList();
...
...
this.campaignList = [];
};
Campaigns.prototype.fetchCampaigns = function() {
//Some service call to load the data in this.campaignList
};
});
Now trying to call the same campaign factory in the second controller, getting only the object structure, not getting the data.
//controlertwo.js
ang.controller('controller2', function(campaign){
$scope.campaigns = new campaign();
//Here only the campaign object structure is displayed, but no data for campaignList, ref image 2 attached
console.log($scope.campaigns);
});
Since, factory service is a singleton object, I was expecting for same result as I got in controllerone.js,
Image 1:
Image 2:
In angular factory I would suggest a different approach.Try not to attach anything to the Prototype of a object. Instead you can create an object in the scope of your angular factory, attach what you want to it and return it. For example:
ang.factory('campaign', function ($http) {
var campaign = {};
campaign.method1 = function () {
//..
}
campaign.campaignList = [];
//...
campaign.fetchCampaigns = function () {
//Some service call to load the data in this.campaignList
};
});
//Than in your controllers if campaign is injected you can use it that way:
ang.controller('controller2', function (campaign) {
campaign.fetchCampaigns();// This will fill the list and it will remain filled when other controllers use this factory...
console.log(compaign.campaignList);
});
Anything you dont want to be exposed out of the factory simply do not attach it to the campaign object.
Create campaign in a service. Eg-campaignService
Updated code---
var ang = angular.module('myApp', []);
ang.service('campaignService', function($scope){
var campaign = function(){
this.timePeriodList = buildTimePeriodList();
...
...
this.campaignList = [];
}
return campaign;
});
ang.controller("controller1", ["campaignService",
function($scope, $rootScope, campaignService){
$scope.campaigns=campaignService.campaign();
}
]);
ang.controller("controller2", ["campaignService",
function($scope, $rootScope, campaignService){
$scope.campaigns=campaignService.campaign();
console.log($scope.campaigns);
}
]);
I am trying to include a library of functions, held in a factory, into a controller.
Similar to questions like this:
Creating common controller functions
My main controller looks like this:
recipeApp.controller('recipeController', function ($scope, groceryInterface, ...){
$scope.groceryList = [];
// ...etc...
/* trying to retrieve the functions here */
$scope.groceryFunc = groceryInterface; // would call ng-click="groceryFunc.addToList()" in main view
/* Also tried this:
$scope.addToList = groceryInterface.addToList();
$scope.clearList = groceryInterface.clearList();
$scope.add = groceryInterface.add();
$scope.addUp = groceryInterface.addUp(); */
}
Then, in another .js file, I have created the factory groceryInterface. I've injected this factory into the controller above.
Factory
recipeApp.factory('groceryInterface', function(){
var factory = {};
factory.addToList = function(recipe){
$scope.groceryList.push(recipe);
... etc....
}
factory.clearList = function() {
var last = $scope.prevIngredients.pop();
.... etc...
}
factory.add = function() {
$scope.ingredientsList[0].amount = $scope.ingredientsList[0].amount + 5;
}
factory.addUp = function(){
etc...
}
return factory;
});
But in my console I keep getting ReferenceError: $scope is not defined
at Object.factory.addToList, etc. Obviously I'm guessing this has to do with the fact that I'm using $scope in my functions within the factory. How do I resolve this? I notice that in many other examples I've looked at, nobody ever uses $scope within their external factory functions. I've tried injecting $scope as a parameter in my factory, but that plain out did not work. (e.g. recipeApp.factory('groceryInterface', function(){ )
Any help is truly appreciated!
Your factory can't access your $scope, since it's not in the same scope.
Try this instead:
recipeApp.controller('recipeController', function ($scope, groceryInterface) {
$scope.addToList = groceryInterface.addToList;
$scope.clearList = groceryInterface.clearList;
$scope.add = groceryInterface.add;
$scope.addUp = groceryInterface.addUp;
}
recipeApp.factory('groceryInterface', function () {
var factory = {};
factory.addToList = function (recipe) {
this.groceryList.push(recipe);
}
factory.clearList = function() {
var last = this.prevIngredients.pop();
}
});
Alternatively, you can try using a more object oriented approach:
recipeApp.controller('recipeController', function ($scope, groceryInterface) {
$scope.groceryFunc = new groceryInterface($scope);
}
recipeApp.factory('groceryInterface', function () {
function Factory ($scope) {
this.$scope = $scope;
}
Factory.prototype.addToList = function (recipe) {
this.$scope.groceryList.push(recipe);
}
Factory.prototype.clearList = function() {
var last = this.$scope.prevIngredients.pop();
}
return Factory;
});
You cannot use $scope in a factory as it is not defined. Instead, in your factory functions change the properties of the object the factory is returning, e.g.
factory.addToList = function (recipe) {
this.groceryList.push(recipe);
}
these will then get passed on to your $scope variable
$scope.addToList = groceryInterface.addToList;
// ... = groceryInterface.addToList(); would assign to `$scope.addToList` what is returned, instead of the function itself.
This isn't the exact answer for this question, but I had a similar issues that I solved by simply passing $scope as an argument to a function in my factory. So it won't be the normal $scope, but $scope at the time the function in the factory is called.
app.controller('AppController', function($scope, AppService) {
$scope.getList = function(){
$scope.url = '/someurl'
// call to service to make rest api call to get data
AppService.getList($scope).then(function(res) {
// do some stuff
});
}
});
app.factory('AppService', function($http, $q){
var AppService = {
getList: function($scope){
return $http.get($scope.url).then(function(res){
return res;
});
},
}
return AppService;
});
I am having a problem getting data from a service populated into my view. I have a service defined as such
app.factory('nukeService', function($rootScope, $http) {
var nukeService = {};
nukeService.nuke = {};
//Gets the list of nuclear weapons
nukeService.getNukes = function() {
$http.get('nukes/nukes.json')
.success(function(data) {
nukeService.nukes = data;
});
return nukeService.nukes;
};
return nukeService;
});
and my controller
function NavigationCtrl($scope, $http, nukeService){
/*$http.get('nukes/nukes.json').success(function(data) {
$scope.nukes = data;
});*/
$scope.nukes = nukeService.getNukes();
}
If I use the $http.get from the controller the data populates fine, however, if I try to call the data from the service, I get nothing. I understand that the query is asynchronous but I am having a hard time understanding how to populate the $scope variable once the data is returned. I could use $rootscope to broadcast an event and listen for it in the controller but this does not seem like the correct way to accomplish this. I would really appreciate any advice on how to do this the correct way.
I think this should solve your problem
app.factory('nukeService', function($rootScope, $http) {
var nukeService = {};
nukeService.data = {};
//Gets the list of nuclear weapons
nukeService.getNukes = function() {
$http.get('nukes/nukes.json')
.success(function(data) {
nukeService.data.nukes = data;
});
return nukeService.data;
};
return nukeService;
});
function NavigationCtrl($scope, $http, nukeService){
$scope.data = nukeService.getNukes();
//then refer to nukes list as `data.nukes`
}
This is a problem with object reference.
when you calls nukeService.getNukes() you are getting a reference to a object a then your variable $scope.nukes refers that memory location.
After the remote server call when you set nukeService.nukes = data; you are not changing the object a instead you are changing nukeService.nukes from referencing object a to object b. But your $scope.nukes does not know about this reassignment and it still points to object a.
My solution in this case is to pass a object a with property data and then only change the data property instead of changing reference to a
This should be as follows. As mentioned by NickWiggill's comment, undefined will be assigned to nukeService.data if we do not return promise.
app.factory('nukeService', function($rootScope, $http) {
var nukeService = {};
//Gets the list of nuclear weapons
nukeService.getNukes = function() {
return $http.get('nukes/nukes.json');
};
return nukeService;
});
function NavigationCtrl($scope, $http, nukeService){
nukeService.getNukes().then(function(response){
$scope.data = response.data;
});
}
What I do is that I expose the data straight from the service, and have a method which initializes this data. What is wrong with this?
Service:
app.factory('nukeService', function($scope, $http) {
var data = {};
data.nukes = [];
//Gets the list of nuclear weapons
var getNukes = function() {
$http.get('nukes/nukes.json').success(function(data) {
data.nukes = data;
});
};
// Fill the list with actual nukes, async why not.
getNukes();
return {
data : data
// expose more functions or data if you want
};
});
Controller:
function NavigationCtrl($scope, nukeService){
$scope.data = nukeService.data;
//then refer to nukes list as `$scope.data.nukes`
}