Data change inside Service does not update the Scope - javascript

I am storing my data inside Angular service (to share across controllers) and provide a function to update it:
.factory('DataManager', function($rootScope){
var _json = {init: 'from DataManager'};
return {
json: _json,
changeTo: function (newVal) {
_json = newVal;
console.log("Changing to ", _json);
}
};
})
Then I simply pull the data into controller:
.controller('MainCtrl', function(DataManager){
var MC = this;
MC.json = DataManager.json;
MC.changeTo = DataManager.changeTo;
})
The problem is - when MC.changeTo function is called, it does update _json variable inside the Service, but not in the controller!
Here is JSbin illustrating the problem.
Any idea what I am doing wrong here?

Try this. Your code doesn't work because _json variable is refering to diffrent object each time. angular.copy copies the new object to the same reference.
changeTo: function (newVal) {
angular.copy(newVal, _json);
console.log("Changing to ", _json);
}

Related

Passing variables between controllers using AngularJS

I have two controllers: Controller1 and Controller2
In Controller1's $scope, I have set up all my values I need. Using the data in $scope, I'm trying to run certain functions and pass the return values to Controller2.
I was thinking about making a factory to pass variable from Controller1 to Controller2. However, I realized all input values I need lives in Controller 1. I wonder whether factory can persist the data when it runs in Controller1 and return that data when it runs again in Controller2.
Thanks
Factory is a singleton so it can be used to share data among different controllers or directives. Take a look at the fiddler here. I have created a factory 'sharedContext' which can be used to share any key-value pair across controllers using different $scope.
Factory
myApp.factory("sharedContext", function() {
var context = [];
var addData = function(key, value) {
var data = {
key: key,
value: value
};
context.push(data);
}
var getData = function(key) {
var data = _.find(context, {
key: key
});
return data;
}
return {
addData: addData,
getData: getData
}
});
From the controller that needs to share the object can call the 'addData' method of the factory to store the data under a key. The other controllers/directives which are interested in accessing the shared data can do so by calling the 'getData' method and passing the correct key.
Controller (Sharing Data)
function MyCtrl_1($scope, sharedContext) {
$scope.input_1 = 5;
$scope.input_2 = 15;
$scope.add = function() {
$scope.result = $scope.input_1 + $scope.input_2;
sharedContext.addData("Result", $scope.result)
}
}
Controller (accessing shared data)
function MyCtrl_2($scope, sharedContext) {
$scope.getData = function() {
$scope.result = sharedContext.getData("Result").value;
}
}
The only assumption here is that both the controllers need to use the exact key to share the data. To streamline the process you can use a constant provider to share the keys. Also note that I have used underscore.js to look for the key in the shared context dictionary.
This is the simplest solution that you can come up with. As you can see the factory is a simple object and because of that construct it's passed by reference not by value that means in both controller dataFactory is the same
http://plnkr.co/edit/eB4g4SZyfcJrCQzqIieD?p=preview
var app = angular.module('plunker', []);
app.controller('ControllerOne', function (dataFactory) {
this.formFields = dataFactory
});
app.controller('ControllerTwo', function (dataFactory) {
this.formData = dataFactory
});
app.factory('dataFactory', function () {
return {};
})
edit
app.factory('dataFactory', function () {
var factory = {
method1: function (arg) {
console.log('method1: ', arg)
factory.method2('called from method1')
},
method2: function (arg) {
console.log('method2: ', arg)
}
}
return factory;
})

How do I use parameters + dependency injection in a service

Here is what I want to do
(function(){angular.module('app').factory("loadDataForStep",ls);
ls.$inject = ['$scope','stepIndex']
function ls ($scope, stepIndex) {
if ($routeParams.code != undefined) {
$scope.code = $routeParams.code;
$scope.retrieveData($routeParams.code);
}
$rootScope.stepIndex = stepIndex-1;
$rootScope.currentStep = stepIndex;
$rootScope.resultsLoaded = false;
if (!fieldDefinitionsLoaded) {
loadAllElementsDefinition();
loadStepsWithOverrides(stepIndex, loadStep);
} else {
loadStep(stepIndex);
}
}
})();
I know there are plenty of issues here, but the issue of the moment (the question) is How do I get $scope injected and pass step index as a parameter? As you can see, $scope needs to come from angular, but I need to provide stepIndex.
Any help is appreciated.
Service don't have scope So can't inject scope in factory.
Scope is an instance of controller.
If you wanna to deal scope object in factory then declare variable in factory then bind factory with scope variable.
Then try kinda like this
var app = angular.module("app",[]);
app.factory("mySvc",function(){
return {
dataList : []
}
});
app.controller("myCtrl",function($scope,mySvc){
$scope.model=mySvc;
console.log($scope.model);
});

Angular binding to service value not updating

I cannot get a binded service value to update when it is changed. I have tried numerous methods of doing so but none of them have worked, what am I doing wrong? From everything I have seen, this seems like it should work...
HTML:
<div class="drawer" ng-controller="DrawerController">
{{activeCountry}}
</div>
Controller:
angular.module('worldboxApp')
.controller('DrawerController', ['$scope', 'mapService', function($scope, mapService) {
$scope.$watch(function() { return mapService.activeCountry }, function(newValue, oldValue) {
$scope.activeCountry = mapService.activeCountry;
});
}]);
Service:
angular.module('worldboxApp').
service('mapService', function(dbService, mapboxService, userService) {
this.init = function() {
this.activeCountry = {};
}
this.countryClick = function(e) {
this.activeCountry = e.layer.feature;
};
this.init();
});
I put a break point to make sure the mapService.activeCountry variable is being changed, but all that ever shows in the html is {}.
If you work with objects and their properties on your scope, rather than directly with strings/numbers/booleans, you're more likely to maintain references to the correct scope.
I believe the guideline is that you generally want to have a '.' (dot) in your bindings (esp for ngModel) - that is, {{data.something}} is generally better than just {{something}}. If you update a property on an object, the reference to the parent object is maintained and the updated property can be seen by Angular.
This generally doesn't matter for props you're setting and modifying only in the controller, but for values returned from a service (and that may be shared by multiple consumers of the service), I find it helps to work with an object.
See (these focus on relevance to ngModel binding):
https://github.com/angular/angular.js/wiki/Understanding-Scopes
If you are not using a .(dot) in your AngularJS models you are doing it wrong?
angular.module('worldboxApp', []);
/* Controller */
angular.module('worldboxApp')
.controller('DrawerController', ['$scope', 'mapService',
function($scope, mapService) {
//map to an object (by ref) rather than just a string (by val), otherwise it's easy to lose reference
$scope.data = mapService.data;
$scope.setCountry = setCountry; //see below
function setCountry(country) {
// could have just set $scope.setCountry = mapService.setCountry;
// however we can wrap it here if we want to do something less generic
// like getting data out of an event object, before passing it on to
// the service.
mapService.setCountry(country);
}
}
]);
/* Service */
angular.module('worldboxApp')
.service('mapService', ['$log',
function($log) {
var self = this; //so that the functions can reference .data; 'this' within the functions would not reach the correct scope
self.data = {
activeCountry: null
}; //we use an object since it can be returned by reference, and changing activeCountry's value will not break the link between it here and the controller using it
_init();
function _init() {
self.data.activeCountry = '';
$log.log('Init was called!');
}
this.setCountry = function _setCountry(country) {
$log.log('setCountry was called: ' + country);
self.data.activeCountry = country;
}
}
]);
<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.2.28/angular.min.js"></script>
<div ng-app="worldboxApp">
<div ng-controller="DrawerController">
<button ng-click="setCountry('USA')">USA</button>
<br />
<button ng-click="setCountry('AUS')">AUS</button>
<br />Active Country: {{data.activeCountry}}
</div>
</div>
In some case $watch is not working with factory object. Than you may use events for updates.
app.factory('userService',['$rootScope',function($rootScope){
var user = {};
return {
getFirstname : function () {
return user.firstname;
},
setFirstname : function (firstname) {
user.firstname = firstname;
$rootScope.$broadcast("updates");
}
}
}]);
app.controller('MainCtrl',['userService','$scope','$rootScope', function(userService,$scope,$rootScope) {
userService.setFirstname("bharat");
$scope.name = userService.getFirstname();
$rootScope.$on("updates",function(){
$scope.name = userService.getFirstname();
});
}]);
app.controller('one',['userService','$scope', function(userService,$scope) {
$scope.updateName=function(){
userService.setFirstname($scope.firstname);
}
}]);
Here is the plunker
Note:- In Some case if broadcast event is not fired instantly you may use $timeout. I have added this in plunker and time depends on your needs. this will work for both factories and services.

AngularJS automatically updating controller data by service

I'm having some basic problems with angular at the moment. I just wrote a service that reads the temperature of an external device in an interval of five seconds. The service saves the new temperature into a variable and exposes it via a return statement. This looks kind of this (simplified code):
angular.service("tempService", ["$interval", function ($interval) {
//revealing module pattern
var m_temp = 0,
requestTemp = function() {//some logic here},
onResponseTemp = function (temp) {
m_temp = temp;
},
//some other private functions and vars ...
foo = bar;
//request new temperture every 5s, calls onResponseTemp after new data got received
$interval(requestTemp, 5000);
return {
getTemp = function(){return m_temp;}
}
}]);
I use a controller to fetch the data from the service like this:
angular.controller("tempCtrl", ["$scope", "tempService", function ($scope, tempService) {
$scope.temp = tempService.getTemp();
}]);
In my view I access it like this:
<div ng-controller="tempCtrl">
<p>{{temp}}</p>
</div>
But I only get 0 and the value never changes. I have tried to implement a custom Pub/Sub pattern so that on a new temperature my service fires an event that my controller is waiting for to update the temperature on the scope. This approach works just fine but I'm not sure if this is the way to go as angular brings data-binding and I thought something this easy had to work by itself ;)
Help is really appreciated.
Please see here http://jsbin.com/wesucefofuyo/1/edit
var app = angular.module('app',[]);
app.service("tempService", ["$interval", function ($interval) {
//revealing module pattern
var m_temp = {
temp:0,
time:null
};
var requestTemp = function() {
m_temp.temp++;
m_temp.time = new Date();
};
var startTemp = function() {
$interval(requestTemp, 3000);
};
return {
startTemp :startTemp,
m_temp:m_temp
};
}]);
app.controller('fCtrl', function($scope,tempService){
$scope.temp = tempService;
$scope.temp.startTemp();
});
You are returning a primitive from your service, if you want to update an primative you need to reftech it. You should return an object, as on object is passed by reference, you get the actual values in your controller.
do this in your service:
return m_temp;
And this in your controller:
$scope.temp = tempService;
and your view will update as soon as the service gets updated.
Does this help you?
i think you should use $interval in controller ot in service
$interval(tempService.getTemp(), 5000);

AngularJS: Reassigning an object vs. replacing it in a controller

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;
});

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