AngularJS service object is not being updated across views/controllers - javascript

I have a factory, "itemData", that holds a service.
app.factory('itemData', function () {
var itemData = {
Title: 'I should be different',
getTitle: function () {
return itemData.Title;
},
setTitle: function (title) {
return itemData.Title=title;
},
// This is the function to call all of the sets for the larger object
editItem: function (entry)
{
itemData.setTitle(entry);
}
};
return itemData;
});
I have 2 controllers (in different files) associated with 2 separate views.
The first:
// IndexCtrl
app.controller("IndexCtrl", ['$scope','$window','itemData',
function($scope, $window, itemData) {
var entry = "I'm different";
// After a submit is clicked
$scope.bttnClicked = function (entry) {
itemData.editItem(entry);
console.log(itemData.getTitle(); //<--itemData.Title has changed
// moves to page with other controller
$window.location.href = "edit.html";
};
}
]);
and the second, which is not doing what I want:
app.controller("editItemCtrl", ['$scope', '$window', 'itemData',
function ($scope, $window, itemData){
$scope.item = {
"Title": itemData.getTitle(), //<--- Title is "I should be different"
}
}]);

Do you have some kind of router in place in your Angular app? When you change the location href, is it actually causing full page reload?
Services are held in memory and therefore will not maintain state across page reloads.

I consider that the expression ['$scope', '$window', 'itemData',
function ($scope, $window, itemData) force to initialize the dependency injection and for this reason you had two different object.
if you see the doc https://docs.angularjs.org/guide/controller there is a section called Setting up the initial state of a $scope object in this section was described the case of scope but I consider that may be extended at the list of the service in the [...] even in the angular.module(moduleName,[...]) if the [....] are filled the functin return a new module and only for empty square bracket return the current module instance
I hop that this can help you

Related

Common JS file to share variable and methods between two controllers

I have two pages where I have 1 common tab which contains some functionality. I have already code ready for that tab for 1 page and now I want to reuse all that code in my second page without duplicating the code.
For example, this is my code for page 1 of tab :
app.controller('myCtrl', ['$scope', '$window', 'myService', '$filter', function ($scope, $window, myService,$filter) {
$scope.myObj = [
{id:1,location : null},
{id:2,location : null}
]
//Lots of other variables here which are common and will be used in both the tabs and lots of methods which are also common
}]);
$scope.myObj is heavily used in all methods which will be common in both the tabs so I would like to have 1 common js file in which I will keep all this common variables and methods so that I don't have to copy-paste all these methods in both the controller of 2 pages to avoid code duplication.
I found 1 example like below but I am not getting how to share methods and complex variables like my $scope.myObj:
How to share common logic between controllers?
You can simply use angular factory and use it among your controllers to get common variable values. This is one of many possible ways
Create a factory where you'll place common variable values
angular.module("commonmodule", [])
.factory('sharedFactory', function () {
var sharedVariable = 1;
return {
getSharedValue : function () {
return sharedVariable;
},
setSharedValue : function (newValue) {
sharedVariable = newValue;
}
}
}});
Just inject above factory in your controller and use them:
First Controller :
angular.module('maincontrollerone', ["commonmodule"])
.controller('controllerone', ["$scope", "sharedFactory", function ($scope, sharedFactory) {
sharedFactory.setSharedValue("someValueFromCtr1");
}
Second Controller
angular.module('maincontrollertwo', ["commonmodule"])
.controller('controllertwo', ["$scope", "sharedFactory", function ($scope, sharedFactory) {
$scope.value1 = sharedFactory.getSharedValue();
// value of $scope.value1 = 'someValueFromCtr1';
}
Create an Angular Service service, maybe we can use myService.
In the service, Make sure that you are not reseting the reference of the sharedObject by assigning new values to it. You have to change the value only.
Ex:in myService
app.service('myService', ['configService', '$http', '$log', '$q',
function (configService, $http, $log, $q) {
var self = this;
var self.sharedObjects ={};
}
add all the objects that are shared as properties of myService.sharedObjects
DO NOT assign new value to myService.shareObjects, but u can set properties to myService.shareObjects like
myService.shareObjects.prop1,myService.shareObjects.prop2

Angular: Not able to access variables in controller using service

I am trying to share a variable between a controller and a function. But i get an error from the controller, saying this:
TypeError: Cannot read property 'getSet' of undefined
I have gone through numerous tutorials, but don't know where am I going wrong.
My service code is like this:
app.service('shareData', function() {
var selected = ["plz", "print", "something"];
var putSet = function(set) {
selected = set;
};
var getSet = function() {
return selected;
};
return {
putSet: putSet,
getSet: getSet
};
});
I am able to reach selected from my function defined like this:
setDisplay = function($scope, $mdDialog, shareData) {
console.log(shareData.getSet()); // this is working
$scope.selected = shareData.getSet();
$scope.hide = function() {
$mdDialog.hide();
};
$scope.cancel = function() {
$mdDialog.cancel();
};
$scope.answer = function(answer) {
$mdDialog.hide(answer);
};
};
My controller is like this:
app.controller('topicController', ['$scope', '$http', '$mdDialog', 'shareData',
function ($scope, $http, $mdDialog, $mdToast, shareData) {
console.log(shareData.getSet()); // NOT WORKING
}]);
You had extra $mdToast in your topicController controller's factory function, you need to remove it.
The reason behind it was not working is, currently you had 4 dependency mentioned in array like ['$scope', '$http', '$mdDialog', 'shareData', function & then you are using its instance inside the function next to DI array. Inside that function you had actually 5 dependencies where $mdToast extra. So behind the scene what happening is $scope of function hold an value of '$scope' DI array likewise you go right to left. But when it comes to $mdToast(in controller function) it was holding a value of 'shareData'(of DI array) & then the next parameter shareData get nothing.
app.controller('topicController', ['$scope', '$http', '$mdDialog', 'shareData',
function ($scope, $http, $mdDialog, shareData) { //<--removed $mdToast
console.log(shareData.getSet());
}
]);
NOTE: You are using DI inline array annotation, so the sequence in which dependency are injected in array, in same sequence you should
inject then in underlying factory function.

AngularJS : watching Service properties

Take the following plunk as an example:
http://plnkr.co/edit/vKFevXhhSprzFvesc6bG?p=preview
var app = angular.module('plunker', []);
app.service('SomeService', ['$rootScope', function ($rootScope) {
var service = {
value: false
}
return service;
}]);
app.controller('MainCtrl', ['$scope', 'SomeService', function($scope, SomeService) {
$scope.value = SomeService.value;
//$scope.$watch(function () { return SomeService.value; }, function (data) { $scope.value = data; });
}]);
app.controller('SecondaryCtrl', ['$scope', 'SomeService', function($scope, SomeService) {
$scope.toggleValue = function () {
SomeService.value = !SomeService.value;
}
}]);
2 controllers and a service, 1 controller (SecondaryCtrl) updates a property on the service and the other controller (MainCtrl) references this property and displays it.
Note the $watch expression commented out in MainCtrl - with this line uncommented, everything works as expected but my question - is it necessary? Shouldn't the watch be implicit or am I doing something wrong?
When you assign the value of SomeService.value to your scope variable, you are creating a copy of the variable which is a distinct object from the value inside SomeService. By adding the watch expression you were simply keeping the two variables (the one in the scope and the one in SomeService) synchronised.
The easiest way to go about this is not to copy the value, but create a reference to the service itself. So in MainCtrl
$scope.someService = SomeService;
and in your html
Value: {{someService.value}}
this way you are actually binding to the value inside SomeService.

Is this a good way to keep data in sync between two controllers?

I have got a page layout with two controllers at the same time, one holds the data displayed as kind of side navigation, based on data stored the browsers local storage and at least one other controller, which is bind to a route and view.
I created this little wire frame graphic below which show the page layout:
The second controller is used for manipulating the local stored data and performs actions like adding a new item or deleting an existing one. My goal is to keep the data in sync, if an item got added or deleted by the 'ManageListCrtl' the side navigation using the 'ListCtrl' should get updated immediately.
I archived this by separating the local storage logic into a service which performs a broadcast when the list got manipulated, each controller listens on this event and updates the scope's list.
This works fine, but I'm not sure if there is the best practice.
Here is a stripped down version of my code containing just the necessary parts:
angular.module('StoredListExample', ['LocalObjectStorage'])
.service('StoredList', function ($rootScope, LocalObjectStorage) {
this.add = function (url, title) {
// local storage add logic
$rootScope.$broadcast('StoredList', list);
};
this.delete = function (id) {
// local storage delete logic
$rootScope.$broadcast('StoredList', list);
};
this.get = function () {
// local storage get logic
};
});
angular.module('StoredListExample')
.controller('ListCtrl', function ($scope, StoredList) {
$scope.list = StoredList.get();
$scope.$on('StoredList', function (event, data) {
$scope.list = data;
});
});
angular.module('StoredListExample')
.controller('ManageListCtrl', function ($scope, $location, StoredList) {
$scope.list = StoredList.get();
$scope.add = function () {
StoredList.add($scope.url, $scope.title);
$location.path('/manage');
};
$scope.delete = function (id) {
StoredList.delete(id);
};
$scope.$on('StoredList', function (event, data) {
$scope.list = data;
});
});
I don't see anything wrong with doing it this way. Your other option of course is to just inject $rootScope into both controllers and pub/sub between them with a $rootScope.$broadcast and a $rootScope.$on.
angular.module('StoredListExample')
.controller('ListCtrl', function ($scope, $rootScope) {
$scope.list = [];
$rootScope.$on('StoredList', function (event, data) {
$scope.list = data;
});
});
angular.module('StoredListExample')
.controller('ManageListCtrl', function ($scope, $rootScope, $location) {
$scope.list = [];
$scope.add = function () {
//psuedo, not sure if this is what you'd be doing...
$scope.list.push({ url: $scope.url, title: $scope.title});
$scope.storedListUpdated();
$location.path('/manage');
};
$scope.delete = function (id) {
var index = $scope.list.indexOf(id);
$scope.list.splice(index, 1);
$scope.storedListUpdated();
};
$scope.storedListUpdated = function () {
$rootScope.$broadcast('StoredList', $scope.list);
};
});
Additionally, you can achieve this in a messy but fun way by having a common parent controller. Whereby you would $emit up a 'StoredListUpdated' event from 'ManageListCtrl' to the parent controller, then the parent controller would $broadcast the same event down to the 'ListCtrl'. This would allow you to avoid using $rootScope, but it would get pretty messy in terms of readability as you add more events in this way.
It is always a better practice to use a common service that is a singleton for sharing the data between the 2 controllers - just make sure you use only references and not creating a local object in one of the controllers that should actually be in the service

Maintain model of scope when changing between views in AngularJS

I am learning AngularJS. Let's say I have /view1 using My1Ctrl, and /view2 using My2Ctrl; that can be navigated to using tabs where each view has its own simple, but different form.
How would I make sure that the values entered in the form of view1 are not reset, when a user leaves and then returns to view1 ?
What I mean is, how can the second visit to view1 keep the exact same state of the model as I left it ?
I took a bit of time to work out what is the best way of doing this. I also wanted to keep the state, when the user leaves the page and then presses the back button, to get back to the old page; and not just put all my data into the rootscope.
The final result is to have a service for each controller. In the controller, you just have functions and variables that you dont care about, if they are cleared.
The service for the controller is injected by dependency injection. As services are singletons, their data is not destroyed like the data in the controller.
In the service, I have a model. the model ONLY has data - no functions -. That way it can be converted back and forth from JSON to persist it. I used the html5 localstorage for persistence.
Lastly i used window.onbeforeunload and $rootScope.$broadcast('saveState'); to let all the services know that they should save their state, and $rootScope.$broadcast('restoreState') to let them know to restore their state ( used for when the user leaves the page and presses the back button to return to the page respectively).
Example service called userService for my userController :
app.factory('userService', ['$rootScope', function ($rootScope) {
var service = {
model: {
name: '',
email: ''
},
SaveState: function () {
sessionStorage.userService = angular.toJson(service.model);
},
RestoreState: function () {
service.model = angular.fromJson(sessionStorage.userService);
}
}
$rootScope.$on("savestate", service.SaveState);
$rootScope.$on("restorestate", service.RestoreState);
return service;
}]);
userController example
function userCtrl($scope, userService) {
$scope.user = userService;
}
The view then uses binding like this
<h1>{{user.model.name}}</h1>
And in the app module, within the run function i handle the broadcasting of the saveState and restoreState
$rootScope.$on("$routeChangeStart", function (event, next, current) {
if (sessionStorage.restorestate == "true") {
$rootScope.$broadcast('restorestate'); //let everything know we need to restore state
sessionStorage.restorestate = false;
}
});
//let everthing know that we need to save state now.
window.onbeforeunload = function (event) {
$rootScope.$broadcast('savestate');
};
As i mentioned this took a while to come to this point. It is a very clean way of doing it, but it is a fair bit of engineering to do something that i would suspect is a very common issue when developing in Angular.
I would love to see easier, but as clean ways to handle keeping state across controllers, including when the user leaves and returns to the page.
A bit late for an answer but just updated fiddle with some best practice
jsfiddle
var myApp = angular.module('myApp',[]);
myApp.factory('UserService', function() {
var userService = {};
userService.name = "HI Atul";
userService.ChangeName = function (value) {
userService.name = value;
};
return userService;
});
function MyCtrl($scope, UserService) {
$scope.name = UserService.name;
$scope.updatedname="";
$scope.changeName=function(data){
$scope.updateServiceName(data);
}
$scope.updateServiceName = function(name){
UserService.ChangeName(name);
$scope.name = UserService.name;
}
}
$rootScope is a big global variable, which is fine for one-off things, or small apps.
Use a service if you want to encapsulate your model and/or behavior (and possibly reuse it elsewhere). In addition to the google group post the OP mentioned, see also https://groups.google.com/d/topic/angular/eegk_lB6kVs/discussion.
Angular doesn't really provide what you are looking for out of the box. What i would do to accomplish what you're after is use the following add ons
UI Router & UI Router Extras
These two will provide you with state based routing and sticky states, you can tab between states and all information will be saved as the scope "stays alive" so to speak.
Check the documentation on both as it's pretty straight forward, ui router extras also has a good demonstration of how sticky states works.
I had the same problem, This is what I did:
I have a SPA with multiple views in the same page (without ajax), so this is the code of the module:
var app = angular.module('otisApp', ['chieffancypants.loadingBar', 'ngRoute']);
app.config(['$routeProvider', function($routeProvider){
$routeProvider.when('/:page', {
templateUrl: function(page){return page.page + '.html';},
controller:'otisCtrl'
})
.otherwise({redirectTo:'/otis'});
}]);
I have only one controller for all views, but, the problem is the same as the question, the controller always refresh data, in order to avoid this behavior I did what people suggest above and I created a service for that purpose, then pass it to the controller as follows:
app.factory('otisService', function($http){
var service = {
answers:[],
...
}
return service;
});
app.controller('otisCtrl', ['$scope', '$window', 'otisService', '$routeParams',
function($scope, $window, otisService, $routeParams){
$scope.message = "Hello from page: " + $routeParams.page;
$scope.update = function(answer){
otisService.answers.push(answers);
};
...
}]);
Now I can call the update function from any of my views, pass values and update my model, I haven't no needed to use html5 apis for persistence data (this is in my case, maybe in other cases would be necessary to use html5 apis like localstorage and other stuff).
An alternative to services is to use the value store.
In the base of my app I added this
var agentApp = angular.module('rbAgent', ['ui.router', 'rbApp.tryGoal', 'rbApp.tryGoal.service', 'ui.bootstrap']);
agentApp.value('agentMemory',
{
contextId: '',
sessionId: ''
}
);
...
And then in my controller I just reference the value store. I don't think it holds thing if the user closes the browser.
angular.module('rbAgent')
.controller('AgentGoalListController', ['agentMemory', '$scope', '$rootScope', 'config', '$state', function(agentMemory, $scope, $rootScope, config, $state){
$scope.config = config;
$scope.contextId = agentMemory.contextId;
...
Solution that will work for multiple scopes and multiple variables within those scopes
This service was based off of Anton's answer, but is more extensible and will work across multiple scopes and allows the selection of multiple scope variables in the same scope. It uses the route path to index each scope, and then the scope variable names to index one level deeper.
Create service with this code:
angular.module('restoreScope', []).factory('restoreScope', ['$rootScope', '$route', function ($rootScope, $route) {
var getOrRegisterScopeVariable = function (scope, name, defaultValue, storedScope) {
if (storedScope[name] == null) {
storedScope[name] = defaultValue;
}
scope[name] = storedScope[name];
}
var service = {
GetOrRegisterScopeVariables: function (names, defaultValues) {
var scope = $route.current.locals.$scope;
var storedBaseScope = angular.fromJson(sessionStorage.restoreScope);
if (storedBaseScope == null) {
storedBaseScope = {};
}
// stored scope is indexed by route name
var storedScope = storedBaseScope[$route.current.$$route.originalPath];
if (storedScope == null) {
storedScope = {};
}
if (typeof names === "string") {
getOrRegisterScopeVariable(scope, names, defaultValues, storedScope);
} else if (Array.isArray(names)) {
angular.forEach(names, function (name, i) {
getOrRegisterScopeVariable(scope, name, defaultValues[i], storedScope);
});
} else {
console.error("First argument to GetOrRegisterScopeVariables is not a string or array");
}
// save stored scope back off
storedBaseScope[$route.current.$$route.originalPath] = storedScope;
sessionStorage.restoreScope = angular.toJson(storedBaseScope);
},
SaveState: function () {
// get current scope
var scope = $route.current.locals.$scope;
var storedBaseScope = angular.fromJson(sessionStorage.restoreScope);
// save off scope based on registered indexes
angular.forEach(storedBaseScope[$route.current.$$route.originalPath], function (item, i) {
storedBaseScope[$route.current.$$route.originalPath][i] = scope[i];
});
sessionStorage.restoreScope = angular.toJson(storedBaseScope);
}
}
$rootScope.$on("savestate", service.SaveState);
return service;
}]);
Add this code to your run function in your app module:
$rootScope.$on('$locationChangeStart', function (event, next, current) {
$rootScope.$broadcast('savestate');
});
window.onbeforeunload = function (event) {
$rootScope.$broadcast('savestate');
};
Inject the restoreScope service into your controller (example below):
function My1Ctrl($scope, restoreScope) {
restoreScope.GetOrRegisterScopeVariables([
// scope variable name(s)
'user',
'anotherUser'
],[
// default value(s)
{ name: 'user name', email: 'user#website.com' },
{ name: 'another user name', email: 'anotherUser#website.com' }
]);
}
The above example will initialize $scope.user to the stored value, otherwise will default to the provided value and save that off. If the page is closed, refreshed, or the route is changed, the current values of all registered scope variables will be saved off, and will be restored the next time the route/page is visited.
You can use $locationChangeStart event to store the previous value in $rootScope or in a service. When you come back, just initialize all previously stored values. Here is a quick demo using $rootScope.
var app = angular.module("myApp", ["ngRoute"]);
app.controller("tab1Ctrl", function($scope, $rootScope) {
if ($rootScope.savedScopes) {
for (key in $rootScope.savedScopes) {
$scope[key] = $rootScope.savedScopes[key];
}
}
$scope.$on('$locationChangeStart', function(event, next, current) {
$rootScope.savedScopes = {
name: $scope.name,
age: $scope.age
};
});
});
app.controller("tab2Ctrl", function($scope) {
$scope.language = "English";
});
app.config(function($routeProvider) {
$routeProvider
.when("/", {
template: "<h2>Tab1 content</h2>Name: <input ng-model='name'/><br/><br/>Age: <input type='number' ng-model='age' /><h4 style='color: red'>Fill the details and click on Tab2</h4>",
controller: "tab1Ctrl"
})
.when("/tab2", {
template: "<h2>Tab2 content</h2> My language: {{language}}<h4 style='color: red'>Now go back to Tab1</h4>",
controller: "tab2Ctrl"
});
});
<!DOCTYPE html>
<html>
<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.6.9/angular.min.js"></script>
<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.6.9/angular-route.js"></script>
<body ng-app="myApp">
Tab1
Tab2
<div ng-view></div>
</body>
</html>

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