How to DRY up $scope-manipulating code across controllers in angularJS - javascript

Pardon if this question is a total blow-off... Just getting warmed-up into the world angularJS.
I have these two controllers: seekerController and wizardController...
Inside the wizardController, I have a chat Scope object, and I have implemented a bunch of functions that are manipulating this chat Scope object.
Going back to the other controller now, ( seekerController ), I discover that I need to have basically a direct replica of this chat Scope object and all the other functions manipulating it as I have inside wizardController
The obvious way is just to copy all these into my other controller, and my work is done under a minute, but then I'll have a lot of repeated stuffs everywhere...
So: I'm looking for a way where I can have this(the code) in a single place, but still be able to have access to this chat Scope object from both controllers, as well as all the other functions working seamlessly.
Update - add code samples:
//seekerController
angular.module('cg.seeker', [])
.controller('SeekerController', ['$scope', 'seekerService', 'timeService', 'chatService', '$stateParams', 'toastr',
function ($scope, seekerService, timeService, chatService, $stateParams, toastr) {
...
// THE CHAT BUSINESS
$scope.chat = { close: true };
chatService.unreadCount(function(count){
$scope.chat.unreadCount = count;
$scope.$apply();
});
chatService.listDialogs( function (dialogList) {
$scope.chat.dialogList = dialogList.items;
$scope.$apply();
} );
$scope.endChat = function () {
$scope.chat.close = true;
}
$scope.chatBox = function (dialogId, occupants_ids) {
$scope.chat.opponentId = getOpponentId(occupants_ids);
chatService.getMessages( dialogId, function (messageList) {
$scope.chat.messages = messageList.items;
$scope.chat.close = false;
$scope.$apply();
});
}
var getOpponentId = function (opponentId) {
if(typeof(opponentId) != 'object') {
return opponentId;
} else {
return opponentId.filter(function(x) { return x != $scope.seeker.chat_user.chat_id_string; })[0];
}
}
$scope.sendMsg = function (opponentId) {
var msg = {
type: 'chat',
body: $scope.chat.msg,
extension: {
save_to_history: 1,
}
};
chatService.sendMsg(opponentId, msg);
$scope.chat.msg = '';
}
...
I now have an exact replica of the above code in a second controller WizardController. Exactly same, with no changes... and even a third controller have some of these, though not all.

The next level of abstraction to angularjs controllers are
Factory
Service
Provider
You could use a service called maybe chatService which could contain the common code. You can inject the service into any controller which needs the common functionality and invoke the methods on the Service.
Do note that you could use any of the above three options even though I have mentioned just Service in the above statement.
EDIT 1:
You could move the common parts of the code from Controller to Service.
For example:- You could move the construction of msg object from controller to chatService. You controller would be simply -
$scope.sendMsg = function (opponentId) {
chatService.sendMsg(opponentId);
$scope.chat.msg = '';
}
And your chatService would be doing the hard-work.
$chatService.sendMsg = function (opponentId) {
var msg = {
type: 'chat',
body: $scope.chat.msg,
extension: {
save_to_history: 1,
}
};
sendMsg(opponentId, msg);
}
After simplifying the Controllers you could revisit to see if you could use only one controller instead of 3 as they seem to be doing similar function.

Related

Properly using an Angular MVC setup

Feel free to clear up any misunderstandings you see here; I'm not a front end guy.
Now, I've read that much of the logic shouldn't exist in the controller, and that it should be put somewhere else. But most places I look that show code don't specify which file it belongs in. On this project that I've inherited I have 4 files that deal with the main functionality:
A controller - autoDeploy.js
A service - autoDeploy.service.js
A module - autoDeploy.module.js
Directives - directives.js
directives.js just contains the templates that I want to inject into the DOM upon the click of a button, the directives will be referenced later.
autoDeploy.module.js does all of the module.config and $stateProvider routing stuff; I don't touch it beyond my initial modification to point to the new page I'm making so it can be properly routed to.
autoDeploy.service.js: In the examples I've seen, the .factory()'s (or .service()) last parameter usually opens up as a function, and all of the functionality in the file happens inside there. Mine isn't like that, it's an iife with the factory being a standalone command followed by what looks like a constructor. Here's what I have:
(function () { //start iife
'use strict';
angular.module('gms.autoDeploy')
.factory('AutoDeployService', ["$http", "$q", "$log", "$cookies", "APP_CONFIGS", "SweetAlert", "$timeout", "GridSettingsService", "APP_USER", AutoDeployService]);
function AutoDeployService($http, $q, $log, $cookies, APP_CONFIGS, $timeout, SweetAlert, GridSettingsService, APP_USER) {
//return service object at bottom of function
function returnOne() {
return "one";
}
var service = {
returnOne: returnOne
};
return service;
} //end AutoDeployService
}()); //end iife
Why did the original developer...
Use as an iife?
Return the service variable after making it a function mapping?
Put all of the functionality in the constructor like function?
My guess to the above 2nd and 3rd answers is that it is the constructor for the service and the controller can some how know it's a usable object because we pass it in as a parameter to the controller as you can see on the top line of the code below. I also don't know much about the parameters for the "constructor", but I can look those up later.
Now for the controller. Unlike the service above, the controller declaration does open up as a function in the parameters of .controller() as I've seen other places. Here it is, simplified (methods with similar functionality are cut out):
angular.module("gms.autoDeploy").controller('AutoDeployController', ['$scope', '$compile', 'AutoDeployService',
function ($scope, $compile, AutoDeployService) {
var vm = this;
init();
function init() {
vm.isInstantiated = true;
vm.data = {
"parameter": []
};
}
// calling a function from the service to show that we can pass
// data from controller to service
vm.change = function () {
vm.message = AutoDeployService.returnOne("not one");
};
//function assigned to button click on the DOM allowing
// the directive to inject the template where the <tib-copy> tag is
vm.addCopy = function (ev, attrs) {
var copy = angular.element(document.createElement('copy'));
var el = $compile(copy)(vm);
angular.element(document.getElementsByTagName("tib-copy")).append(copy);
vm.insertHere = el;
};
// This method extracts data from the following fields dynamically added by the click of a button:
// - TIBCO Server(s)
// - TIBCO Domain(s)
// - TIBCO Application(s)
vm.getTibPromotionData = function () {
// Add all TIBCO servers
var servers = document.getElementsByName("tibServer");
var tibSvrList = [];
for (var i = 0; i < servers.length; i++) {
tibSvrList.push(servers[i].value);
}
// Add all TIBCO domains
var domains = document.getElementsByName("tibDomain");
var tibDomainList = [];
for (i = 0; i < domains.length; i++) {
tibDomainList.push(domains[i].value);
}
// Add all applications
var tibApps = document.getElementsByName("tibApp");
var tibAppList = [];
for (i = 0; i < tibApps.length; i++) {
tibAppList.push(tibApps[i].value);
}
// Add the processed data to the final JSON
vm.data.parameter.push({
"name": "TIBCO_Promotion",
"value": JSON.stringify("[{\"server\":[" + tibSvrList + "]},{\"domain\":[" + tibDomainList + "]},{\"application\":[" + tibAppList + "]}]")
});
};
}
]);
Please, let me know if you see anything in the controller that should belong in the autoDeploy.service.js file. Furthermore, if anyone has experience with this file naming convention, I'd love to hear an explanation as to why there are files named *.service.js and *.module.js, and if the *.service.js file has anything to do with the concept of services and factories, or if it's intended to be conceptual, as if it's just a reference to being the back end services component.

sharing data between controllers in two different ng-app not working via shared service

So I have two different html pages, two different ng-apps and two controllers. I am trying to share data between controllers and different modules.
Below is the basic structure of the application
index.html
- indexController.js
login.html
- loginController.js
sharedService.js
angular.module('sharedService', []).service('SharedService', function() {
var SharedService;
SharedService = (function() {
function SharedService() {
console.log('initializing');
}
var _data;
SharedService.prototype.setData = function( data) {
_data = data;
/* method code... */
};
SharedService.prototype.getData = function( ) {
return _data ;
};
return SharedService;
})();
if (typeof(window.angularSharedService) === 'undefined' || window.angularSharedService === null) {
window.angularSharedService = new SharedService();
}
return window.angularSharedService;});
angular.module("loginApp", ['sharedService'])
controller("loginCtrl",[
'SharedService', function(SharedService){
SharedService.setData(data);
}
angular.module("mainApp", ['sharedService'])
controller("someCtrl",[
'SharedService', function(SharedService){
console.log(SharedService.getData());
}
The thing is since the app is different i am referenceing the
<script src="sharedService.js"></script>
the service gets initialized twice. when i set the data from loginApp sets the data but however when i query the data from mainApp, it retrieves undefined, i suspect this is because the service gets initialized again and is a different instance of sharedService
You are correct, the service will not be shared between two angular apps on different html pages. You will need to persist the data you want to share in somewhere other than memory, such as localStorage or a remote server. https://developer.mozilla.org/en-US/docs/Web/API/Storage/LocalStorage
Just played a bit with it. You can just put the _data you want to share between two apps onto the window object. Like so
angular.module('serv', [])
.factory('MyFactory', function () {
window._data = 'default';
return {
setData: function (val) {
console.log('setData() called with val == ', val);
window._data = val;
},
getData: function () {
return window._data;
},
}
});
See this plunker: http://plnkr.co/edit/4896aiczBjMiCXazB2Kk?p=preview
Though that seems to be somewhat ugly. Probably want to at least namespace it.

Do not understand the controllers in Angular JS

This is a question I am not used to ask, but I feel like this is the only way to understand what I am struggling with. As shown below, there are two functions app.controller() and app.factory(), to me both of them seems to be equal even though if I delete one part the function does not perform its intended task.
Link to plunker: click here (Relevant file is script.js)
What is the difference between these two functions, why cant I have only one of them? I know there must be a simple explanation.
app.controller('MainCtrl', ['$scope', 'ItemsService', function ($scope, ItemsService) {
$scope.newItem = { PlateNumber: '', Description: '', Price: 0 };
$scope.currentItem = null;
$scope.items = ItemsService.getItems();
$scope.addItem = function () {
ItemsService.addItem(angular.copy($scope.newItem));
$scope.newItem = { PlateNumber: '', Description: '', Price: 0 };
};
$scope.updateItem = function (id) {
ItemsService.updateItem(id);
};
$scope.removeItem = function (id) {
ItemsService.removeItem(id);
};
}]);
vs
app.factory('ItemsService', ['$firebase', 'FIREBASE_URI', function ($firebase, FIREBASE_URI) {
var ref = new Firebase(FIREBASE_URI);
var items = $firebase(ref);
var getItems = function () {
return items;
};
var addItem = function (item) {
items.$add(item);
};
var updateItem = function (id) {
items.$save(id);
};
var removeItem = function (id) {
items.$remove(id);
};
return {
getItems: getItems,
addItem: addItem,
updateItem: updateItem,
removeItem: removeItem
}
}]);
Controllers are only instantiated when you need one, (you use ng-controller or controllerAs). So every time you switch to a different route or page, Angular instantiates a controller (it can be the same one that's cleaned up, for example if you refresh the page.)
Angular providers, of which there are a few main kinds - Factory being one of them, are a way to keep data around for the lifetime of the app or even used to pass data between different controllers. The scope of your question is more like: Provider vs Controller, not Factory(which is one type) vs Controller.
In your example above, you have ONE controller, what if you have many? How can you pass data or utility functions to many controllers without writing the same code over and over again? With Providers for one!
Here are some good links for you to check out:
Angular Provider Docs
Blog post by Tyler McGinnis explaining the above further
JSFiddle with Example of a Factory vs a Service

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);
});

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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