inheritance with angularjs .service() - javascript

I have a ServiceA() in module A and variable item is used in html.
angular.module("ModuleA").service("ServiceA", function () {
var item=[];
this.get(){
item.push("A");
}
});
Controller.js
angular.module("ModuleX").controller("Ctrl", function (ServiceA) {
$scope.service=ServiceA;
});
HTML:
<h1>{{service.item}}
</h1>
i am trying to achieve inheritance using angularjs .service(),I want to make serviceA() in moduleA as base service and create a service serviceB() in moduleB and this should inherit base service(serviceA()) and update variable 'item' in serviceA().
Controller code and html code remains same.
Is it possible? Is this a good approach? Can we achieve inheritance/abstraction using angularjs .service()?
angular.module("ModuleB").service("serviceB", function (serviceA) {
serviceA.item="B";
});

Whenever you define a module, you should pass a empty array or
dependencies as the second argument. i.e. angular.module("ModuleA",
[]) or angular.module("ModuleA", ['someDependent']).
The service is in one module whereas the controller is in the other module. So, you need to create a relation between them angular.module("ModuleX", ["ModuleA"]).
You are not returning anything from the service and you have written the method in wrong way.
Plnkr
Working Code
angular.module("ModuleA", []).service("ServiceA", function () {
var item=[];
this.get = function(){
item.push("A");
return item;
}
});
angular.module("ModuleX", ["ModuleA"]).controller("Ctrl", function ($scope, ServiceA) {
$scope.service = ServiceA.get();
console.log($scope);
});

Related

How to add some common code in all the services in angularJs

I am having one condition i.e
if(localstorage.testEnv){
env.apiUrl='testUrl.com';
}else{
env.apiUrl='liveUrl.com';
}
I need to inject this code in all the services. Is there any way I can implement this so that their won't be any code duplication.
Also, would this code work? I am trying to update env const (apiUrl) here?
Simplest way is to make a Utils Service and expose all common functions in this file, in this case a function which checks testEnv from local Storage and returns the corresponding URL. In this case getAPIBaseUrl is the function.
define(["../module"], function(services) {
"use strict";
services.service("Utils", [
"$localStorage",
function($localStorage) {
this.getAPIBaseUrl = function() {
if ($localStorage.testEnv) {
return "testUrl.com";
}
return "liveUrl.com";
};
}
]);
});
Unless the API url can change in the runtime, you may want to define the apiUrl and an AngularJS constant.
var app = angular.module('app', []);
app.constant('apiUrl', (function() {
return localStorage.testEnv ? 'testUrl.com' : 'liveUrl.com'
})());
app.controller('SomeController', function(apiUrl) {
console.log(apiUrl)
});
Main benefit of using a constant is that it can be injected in the configuration phase, e.g:
app.config(function(apiUrl) {
console.log(apiUrl)
})

Angular: is it possible to share data between scopes?

my question is if i can share scopes, for example
i have one function
$scope.init = function(){
$http({
url: url_for('account/getinfo'),
method: "POST",
data: fields
}).success(function (data, status, headers, config) {
$scope.locations = data.stores;
$scope.currentLocation = data.stores.filter(function(store){
return store.mpos_id == $scope.mposid;
});
if ($scope.currentLocation.length > 0) {
$scope.currentLocation = $scope.currentLocation[0];
}
}).error(function (data, status, headers, config) {
});
};
the $scope.currentLocation is an Object!
can i use this obj data in other function?
tried with angular.copy and extend, no success
$scope.getInfo = function(){
$scope.currentLocationData = angular.copy($scope.currentLocation);
}
Services in Angular are singletons, so you could store this data in a service and inject it wherever you need it. It's already considered best practice to separate your data requests into services, so you'd be creating a service anyways.
Here's an example:
First separate your data retrieval logic into a service.
angular.module('app').service('accountDataService', AccountDataService);
function AccountDataService($http){
var service = this;
service.getInfo = function(fields){
return $http.post(url_for('account/getinfo'), fields)
.then(function(response){ return response.data.stores; });
}
}
Then create an account service to share the retrieved data between controllers/components:
angular.module('app').service('accountService', AccountService);
function AccountService(accountDataService){
var service = this;
service.currentLocation = {};
service.locations = [];
service.init = function(fields, mposid){
accountDataService.getInfo(fields).then(function(stores){
service.locations = stores;
var currentLocations = stores.filter(function(store){
return store.mpos_id == mposid;
});
if (currentLocations.length > 0) {
service.currentLocation = currentLocations[0];
}
});
}
}
Now all you have to do in your controllers is inject the accountService.
angular.module('app').run(function(accountService){
accountService.init({ /* your fields */ }, '[your mposid]');
});
angular.module('app').controller('myController', MyController);
function MyController($scope, accountService){
$scope.currentLocation = accountService.currentLocation;
}
Running the init function inside run(..) is just for example. You'd preferably run this in a route resolve function or something like that due to the async nature of the init function.
Bonus note
Avoid using the $scope to pass variables to the view. Use the controllerAs syntax instead. You can check the documentation for more info on how it works, or I suggest you to check out the angular 1.x style guide from John Papa.
Definitely you can copy like that i will work. you can check in below example.
<!DOCTYPE html>
<html>
<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.6.4/angular.min.js"></script>
<body>
<div ng-app ="app" ng-controller ="ctrl">
{{currentLocationData}}
</div>
<script>
angular.module('app', []).controller('ctrl', function($scope){
$scope.currentLocation = 'testing angular copy';
$scope.currentLocationData = angular.copy($scope.currentLocation);
})
</script>
</body>
</html>
If you are looking to share data between two controllers / directives, then you should use a service and inject it in both the controllers / directives.
If you are looking to just create a new copy of / clone the object, then you can use JSON.parse(JSON.stringify($scope.currentLocation))
Hope this helps!
You can access that object in another scope if and only if that scope is a child not isolated of the previous one. In this case your child scope will inherit all the properties of the parent scope too.
So if that code is the scope of a controller, and you have another controller as child of that one, the child one can access that property.
Although it works, a lot of times that's not the best practice to develop things using AngularJS. It will force a dependency among the two controllers and if you will change your code, you could lose the inheritance and break your code.
In these cases the best solution is to define a service which holds the value of the currentLocation. Then inject this service wherever you need to access this value.
I hope it makes sense

Unable to add $scope to service in angularjs? [duplicate]

I have a Service:
angular.module('cfd')
.service('StudentService', [ '$http',
function ($http) {
// get some data via the $http
var path = 'data/people/students.json';
var students = $http.get(path).then(function (resp) {
return resp.data;
});
//save method create a new student if not already exists
//else update the existing object
this.save = function (student) {
if (student.id == null) {
//if this is new student, add it in students array
$scope.students.push(student);
} else {
//for existing student, find this student using id
//and update it.
for (i in students) {
if (students[i].id == student.id) {
students[i] = student;
}
}
}
};
But when I call save(), I don't have access to the $scope, and get ReferenceError: $scope is not defined. So the logical step (for me), is to provide save() with the $scope, and thus I must also provide/inject it to the service. So if I do that like so:
.service('StudentService', [ '$http', '$scope',
function ($http, $scope) {
I get the following error:
Error: [$injector:unpr] Unknown provider: $scopeProvider <- $scope <-
StudentService
The link in the error (wow that is neat!) lets me know it is injector related, and might have to do with order of declaration of the js files. I have tried reordering them in the index.html, but I think it is something more simple, such as the way I am injecting them.
Using Angular-UI and Angular-UI-Router
The $scope that you see being injected into controllers is not some service (like the rest of the injectable stuff), but is a Scope object. Many scope objects can be created (usually prototypically inheriting from a parent scope). The root of all scopes is the $rootScope and you can create a new child-scope using the $new() method of any scope (including the $rootScope).
The purpose of a Scope is to "glue together" the presentation and the business logic of your app. It does not make much sense to pass a $scope into a service.
Services are singleton objects used (among other things) to share data (e.g. among several controllers) and generally encapsulate reusable pieces of code (since they can be injected and offer their "services" in any part of your app that needs them: controllers, directives, filters, other services etc).
I am sure, various approaches would work for you. One is this:
Since the StudentService is in charge of dealing with student data, you can have the StudentService keep an array of students and let it "share" it with whoever might be interested (e.g. your $scope). This makes even more sense, if there are other views/controllers/filters/services that need to have access to that info (if there aren't any right now, don't be surprised if they start popping up soon).
Every time a new student is added (using the service's save() method), the service's own array of students will be updated and every other object sharing that array will get automatically updated as well.
Based on the approach described above, your code could look like this:
angular.
module('cfd', []).
factory('StudentService', ['$http', '$q', function ($http, $q) {
var path = 'data/people/students.json';
var students = [];
// In the real app, instead of just updating the students array
// (which will be probably already done from the controller)
// this method should send the student data to the server and
// wait for a response.
// This method returns a promise to emulate what would happen
// when actually communicating with the server.
var save = function (student) {
if (student.id === null) {
students.push(student);
} else {
for (var i = 0; i < students.length; i++) {
if (students[i].id === student.id) {
students[i] = student;
break;
}
}
}
return $q.resolve(student);
};
// Populate the students array with students from the server.
$http.get(path).then(function (response) {
response.data.forEach(function (student) {
students.push(student);
});
});
return {
students: students,
save: save
};
}]).
controller('someCtrl', ['$scope', 'StudentService',
function ($scope, StudentService) {
$scope.students = StudentService.students;
$scope.saveStudent = function (student) {
// Do some $scope-specific stuff...
// Do the actual saving using the StudentService.
// Once the operation is completed, the $scope's `students`
// array will be automatically updated, since it references
// the StudentService's `students` array.
StudentService.save(student).then(function () {
// Do some more $scope-specific stuff,
// e.g. show a notification.
}, function (err) {
// Handle the error.
});
};
}
]);
One thing you should be careful about when using this approach is to never re-assign the service's array, because then any other components (e.g. scopes) will be still referencing the original array and your app will break.
E.g. to clear the array in StudentService:
/* DON'T DO THAT */
var clear = function () { students = []; }
/* DO THIS INSTEAD */
var clear = function () { students.splice(0, students.length); }
See, also, this short demo.
LITTLE UPDATE:
A few words to avoid the confusion that may arise while talking about using a service, but not creating it with the service() function.
Quoting the docs on $provide:
An Angular service is a singleton object created by a service factory. These service factories are functions which, in turn, are created by a service provider. The service providers are constructor functions. When instantiated they must contain a property called $get, which holds the service factory function.
[...]
...the $provide service has additional helper methods to register services without specifying a provider:
provider(provider) - registers a service provider with the $injector
constant(obj) - registers a value/object that can be accessed by providers and services.
value(obj) - registers a value/object that can only be accessed by services, not providers.
factory(fn) - registers a service factory function, fn, that will be wrapped in a service provider object, whose $get property will contain the given factory function.
service(class) - registers a constructor function, class that will be wrapped in a service provider object, whose $get property will instantiate a new object using the given constructor function.
Basically, what it says is that every Angular service is registered using $provide.provider(), but there are "shortcut" methods for simpler services (two of which are service() and factory()).
It all "boils down" to a service, so it doesn't make much difference which method you use (as long as the requirements for your service can be covered by that method).
BTW, provider vs service vs factory is one of the most confusing concepts for Angular new-comers, but fortunately there are plenty of resources (here on SO) to make things easier. (Just search around.)
(I hope that clears it up - let me know if it doesn't.)
Instead of trying to modify the $scope within the service, you can implement a $watch within your controller to watch a property on your service for changes and then update a property on the $scope. Here is an example you might try in a controller:
angular.module('cfd')
.controller('MyController', ['$scope', 'StudentService', function ($scope, StudentService) {
$scope.students = null;
(function () {
$scope.$watch(function () {
return StudentService.students;
}, function (newVal, oldVal) {
if ( newValue !== oldValue ) {
$scope.students = newVal;
}
});
}());
}]);
One thing to note is that within your service, in order for the students property to be visible, it needs to be on the Service object or this like so:
this.students = $http.get(path).then(function (resp) {
return resp.data;
});
Well (a long one) ... if you insist to have $scope access inside a service, you can:
Create a getter/setter service
ngapp.factory('Scopes', function (){
var mem = {};
return {
store: function (key, value) { mem[key] = value; },
get: function (key) { return mem[key]; }
};
});
Inject it and store the controller scope in it
ngapp.controller('myCtrl', ['$scope', 'Scopes', function($scope, Scopes) {
Scopes.store('myCtrl', $scope);
}]);
Now, get the scope inside another service
ngapp.factory('getRoute', ['Scopes', '$http', function(Scopes, $http){
// there you are
var $scope = Scopes.get('myCtrl');
}]);
Services are singletons, and it is not logical for a scope to be injected in service (which is case indeed, you cannot inject scope in service). You can pass scope as a parameter, but that is also a bad design choice, because you would have scope being edited in multiple places, making it hard for debugging. Code for dealing with scope variables should go in controller, and service calls go to the service.
You could make your service completely unaware of the scope, but in your controller allow the scope to be updated asynchronously.
The problem you're having is because you're unaware that http calls are made asynchronously, which means you don't get a value immediately as you might. For instance,
var students = $http.get(path).then(function (resp) {
return resp.data;
}); // then() returns a promise object, not resp.data
There's a simple way to get around this and it's to supply a callback function.
.service('StudentService', [ '$http',
function ($http) {
// get some data via the $http
var path = '/students';
//save method create a new student if not already exists
//else update the existing object
this.save = function (student, doneCallback) {
$http.post(
path,
{
params: {
student: student
}
}
)
.then(function (resp) {
doneCallback(resp.data); // when the async http call is done, execute the callback
});
}
.controller('StudentSaveController', ['$scope', 'StudentService', function ($scope, StudentService) {
$scope.saveUser = function (user) {
StudentService.save(user, function (data) {
$scope.message = data; // I'm assuming data is a string error returned from your REST API
})
}
}]);
The form:
<div class="form-message">{{message}}</div>
<div ng-controller="StudentSaveController">
<form novalidate class="simple-form">
Name: <input type="text" ng-model="user.name" /><br />
E-mail: <input type="email" ng-model="user.email" /><br />
Gender: <input type="radio" ng-model="user.gender" value="male" />male
<input type="radio" ng-model="user.gender" value="female" />female<br />
<input type="button" ng-click="reset()" value="Reset" />
<input type="submit" ng-click="saveUser(user)" value="Save" />
</form>
</div>
This removed some of your business logic for brevity and I haven't actually tested the code, but something like this would work. The main concept is passing a callback from the controller to the service which gets called later in the future. If you're familiar with NodeJS this is the same concept.
Got into the same predicament. I ended up with the following. So here I am not injecting the scope object into the factory, but setting the $scope in the controller itself using the concept of promise returned by $http service.
(function () {
getDataFactory = function ($http)
{
return {
callWebApi: function (reqData)
{
var dataTemp = {
Page: 1, Take: 10,
PropName: 'Id', SortOrder: 'Asc'
};
return $http({
method: 'GET',
url: '/api/PatientCategoryApi/PatCat',
params: dataTemp, // Parameters to pass to external service
headers: { 'Content-Type': 'application/Json' }
})
}
}
}
patientCategoryController = function ($scope, getDataFactory) {
alert('Hare');
var promise = getDataFactory.callWebApi('someDataToPass');
promise.then(
function successCallback(response) {
alert(JSON.stringify(response.data));
// Set this response data to scope to use it in UI
$scope.gridOptions.data = response.data.Collection;
}, function errorCallback(response) {
alert('Some problem while fetching data!!');
});
}
patientCategoryController.$inject = ['$scope', 'getDataFactory'];
getDataFactory.$inject = ['$http'];
angular.module('demoApp', []);
angular.module('demoApp').controller('patientCategoryController', patientCategoryController);
angular.module('demoApp').factory('getDataFactory', getDataFactory);
}());
Code for dealing with scope variables should go in controller, and service calls go to the service.
You can inject $rootScope for the purpose of using $rootScope.$broadcast and $rootScope.$on.
Otherwise avoid injecting $rootScope. See
Common Pitfalls: $rootScope exists, but it can be used for evil.

Typescript $inject $timeout into a directive ... works in controller, not in link

Stack:
Typescript 1.7 + Angular 1.49
Summary:
I have a directive. I want to $inject angular's $timeout service. It works fine in the directive's controller function, but not in the link function. What am I missing?
Questions:
What did I do wrong?
Is there a better way to $inject the $timeout dependency?
Why will the $timeout service work in the directive's controller but not the link?
MyDirective.ts:
module app.directives {
export class MyDirective {
priority = 0;
restrict = 'E';
templateUrl = 'template.html';
scope = {
'items': '='
};
controller = MyController;
link = MyLink;
static $inject = ['$timeout'];
constructor(private $timeout:ng.ITimeoutService) {
}
}
function MyController($scope:ng.IScope, $timeout:ng.ITimeoutService) {
console.log("controller", $timeout); // function timeout(fn,delay,invokeApply){ the guts here }
$timeout(function () {
console.log("This works fine");
},3000);
}
function MyLink(scope:ng.IScope, element:ng.IAugmentedJQuery, attr:ng.IAttributes, $timeout:ng.ITimeoutService) {
console.log("link to", $timeout); // MyController {}
$timeout(function () {
console.log("This throws the error, TypeError: $timeout is not a function");
},3000);
}
}
Connecting it in directives.ts:
module app.directives {
angular.module('app').directive('MyDirective',['$timeout',($timeout:ng.ITimeoutService) => new MyDirective($timeout) ]);
}
app.ts
module app {
angular.module('app', []);
}
What hasn't worked:
Using this.$timeout in MyLink, with or without including $timeout in the parameters.
I've found several articles and examples that I've tried to make sure I'm following the logic of in my app but can't seem to get it.
Final notes
Typescript-Angular is still new and there are so many best practices that are far from being defined. Part of my team's project is finding some of those.
We have been working on this general structure for a while, so unless there's a compelling reason, please refrain from suggestions that I change the structure of everything too much.
Link functions are not executed directly from directive instance, hence you wont get this as Directive's config instance (which you instantiate via new operator). Also you cannot inject anything to the link function (that is what directive constructor is for) unlike the controller constructor, the arguments to the link function are automatically passed in by the directive execution logic. You could use an arrow operator to resolve this issue.
Example:
export class MyDirective {
priority = 0;
restrict = 'E';
templateUrl = 'template.html';
scope = {
'items': '='
};
controller = MyController;
link:ng.IDirectiveLinkFn = (scope:ng.IScope, element:ng.IAugmentedJQuery, attr:ng.IAttributes) => {
//Here
this.$timeout(function () {
},3000);
};
constructor(private $timeout:ng.ITimeoutService) {
}
}
Or you could bind the context using function.bind. i.e link = MyLink; and access the $timeout using this.$timeout.
If interseted you could take a look at creating some syntactic sugars by using experimental decorators for directives or you could try exploring something like this. However (just my opinion) using a class for directive config seems to be an overkill, you might as well just use a function with static inject.
Link function 4th parameter is the controller instance him self.
If you want to do it you should do something like:
module app.directives {
export class MyDirective {
link = MyLink;
static $inject = ['$timeout'];
constructor(public $timeout:ng.ITimeoutService) {
}
}
function MyLink(scope:ng.IScope, element:ng.IAugmentedJQuery, attr:ng.IAttributes, ctrl:any) {
ctrl.$timeout(function () {
console.log("This throws the error, TypeError: $timeout is not a function");
},3000);
}
}
I know that this is not elegant but I have hard time finding a better solution, what do you think?

AngularJS - Creating a compile function

I'm trying to create a custom compile function, to make it easier to dynamically add HTML to a page.
The argument htmlStr is the incoming HTML to compile. The argument value is a variable that can be added to the scope. The argument compiledHTMLFunc is a function that will be executed with the compiled object. Here's my code:
function compileHTML (htmlStr, value, compiledHTMLFunc)
{
var $injector = angular.injector (["ng", "angularApp"]);
$injector.invoke (function ($rootScope, $compile)
{
$rootScope.value = value;
var obj = angular.element (htmlStr);
var obj2 = $compile (obj)($rootScope);
if (compiledHTMLFunc != null)
compiledHTMLFunc (obj2);
});
}
Here's how I use the function:
compileHTML ("<button class = \"btn btn-primary\">{{ value }}</button>", "Ok", function (element)
{
$(document.body).append (element);
});
Whenever I try to compile the following HTML, the inline {{ value }} doesn't get compiled. Even if I simply change it to {{ 1+1 }}. Why is this?
Update: I dunno why I didn't create a fiddle earlier, here's an example: http://jsbin.com/vuxazuzu/1/edit
The problem appears to be pretty simple. Since you invoke compiler from outside of angular digest cycle you have to invoke it manually to boost the process, for example by wrapping compiledHTMLFunc into $timeout service call:
function compileHTML (htmlStr, scope, compiledHTMLFunc) {
var $injector = angular.injector(["ng", "angularApp"]);
$injector.invoke(function($rootScope, $compile, $timeout) {
$rootScope = angular.extend($rootScope, scope);
var obj = $compile(htmlStr)($rootScope);
if (compiledHTMLFunc != null) {
$timeout(function() {
compiledHTMLFunc(obj);
});
}
});
}
compileHTML('<button class="btn btn-primary">{{value}}</button>', {value: 'Ok'}, function(element) {
angular.element(document.body).append(element);
});
I also improved your code a little. Note how now compileHTML accepts an object instead of single value. It adds more flexibility, so now you can use multiple values in template.
Demo: http://plnkr.co/edit/IAPhQ9i9aVVBwV9MuAIE?p=preview
And here is your updated demo: http://jsbin.com/vuxazuzu/2/edit

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