angular controller is executing before factory complete - javascript

I have moved some common code to factory. but the controller is executing before factory get loaded. In this case i am getting the blank response(zero results)
can anyone suggest the best solution.
here is my angular factory,
app.factory('TabsFactory', function($resource){
var activetabs = {};
activetabs.getDepositAccountDetails = function() {
return $resource('xxxx/:number', {}, {
getDepositAccountDetailsService: {
method: 'GET',
isArray: false
}
});
}
activetabs.getAccountInfo = function(){
return accountinit.accountInfo;
}
activetabs.setAccountInfo = function(accountnumber, result) {
var accountinit = {
accountInfo: []
}
if (result.code == "v") {
activetabs.getDepositAccountDetails().getDepositAccountDetailsService({
number: accountnumber
}).$promise.then(function(response) {
accountinit.accountInfo = response;
//here i am getting the JSON response
}, function(error) {
});
}
return accountinit;
}
return activetabs;
});
controller,
TabsFactory.setAccountInfo(accountnumber, $scope.accountInfo);
$scope.accountInfo = TabsFactory.getAccountInfo();
alert(JSON.stringify($scope.accountInfo));

You should use chain promise to update scope variable, because your accountInfo variable is updated inside $resource promise.
Code
TabsFactory.setAccountInfo(accountnumber, $scope.accountInfo).then(function(data){
$scope.accountInfo = TabsFactory.getAccountInfo();
alert(JSON.stringify($scope.accountInfo));
});
Update
Service method should return promise inorder to continue promise chain
activetabs.setAccountInfo = function(accountnumber, result) {
var accountinit = {
accountInfo: []
}
if (result.code == "v") {
//added return below
return activetabs.getDepositAccountDetails().getDepositAccountDetailsService({
number: accountnumber
}).$promise.then(function(response) {
accountinit.accountInfo = response;
return accountinit.accountInfo;
//here i am getting the JSON response
}, function(error) {
});
}
return accountinit;
}

Yes, this will happen because of JavaScript executing asynchronous operations but your controller in such a way that it expects things to be synchronous operations.
When you call TabsFactory.getAccountInfo() its possible that your $resource('xxxx/:number') is still not completed and response ready for you to process!!
So, what to do? You have make use of promise. I usually have a repository (A factory with method that return promise) to handle server communications. Here is an example:
app.factory('accountRepository', ["$http","$q",function($http,$q){
return {
getDepositAccountDetails : function(id) {
var deferred = $q.defer();
$http.ger('xxx').success(deferred.resolve).error(deferred.reject);
return deferred.promise;
}
};
}] );
My repository will have more operations like add account, update account info etc..
my controller/service then calls these methods as follows:
accountRepository.getDepositAccountDetails(123).then(function(response) {
// Process the response..
}, function(error) {
// Some error occured! handle it
});
doing so, my code gets executed only after I get response from server and data is ready for consumption or display. Hope this helps..
Update: You might want to have a look at this to get the idea ;)

Related

handle a function that returns a promise or a null value

I have defined a function as following :
function getCurrentComponent(){
if($rootRouter._currentInstruction){
return $rootRouter.recognize($rootRouter._currentInstruction.urlPath).then(function (data) {
return data.component.componentType;
});
}else{
return null;
}
}
To call this function I did as following :
factory.getCurrentComponent().then(function (data) {
...
});
The problem is when the getCurrentComponent function returns a null value, the following error is generated :
Cannot read property 'then' of null
How can I solve this ?
Edit:
I forgot to say that I'm limited to use ES5, so I can't work with the object Promise
Use Promise.reject() function.
function getCurrentComponent() {
if ($rootRouter._currentInstruction) {
return $rootRouter.recognize($rootRouter._currentInstruction.urlPath).then(function(data) {
return data.component.componentType;
});
} else {
return Promise.reject('_currentInstruction is fale');
}
}
factory.getCurrentComponent().then(function(data) {
...
}).catch(function(e) {
console.log(e); // Output: _currentInstruction is fale
});
Resource
Promise.reject()
If you're unable to use Promise you can return an object with a function then.
function getCurrentComponent() {
if ($rootRouter._currentInstruction) {
return $rootRouter.recognize($rootRouter._currentInstruction.urlPath).then(function(data) {
return data.component.componentType;
});
} else {
var helperThen = { then: function(fn) { fn(null) } };
return helperThen;
}
}
factory.getCurrentComponent().then(function(data) {
// Check if data is null.
...
});
I cant use the object Promise in ES5.
Use the AngularJS $q Service:
function getCurrentComponent(){
if($rootRouter._currentInstruction){
return $rootRouter.recognize($rootRouter._currentInstruction.urlPath).then(function (data) {
return data.component.componentType;
});
}else{
̶r̶e̶t̶u̶r̶n̶ ̶n̶u̶l̶l̶;̶
return $q.reject(null);
}
}
AngularJS modifies the normal JavaScript flow by providing its own event processing loop. This splits the JavaScript into classical and AngularJS execution context. Only operations which are applied in the AngularJS execution context will benefit from AngularJS data-binding, exception handling, property watching, etc.
The $q Service is a Promises/A+-compliant implementation of promises/deferred objects thst is integrated with the AngularJS framework and its digest cycle.
Convert the function to use a Promise.
function getCurrentComponent(){
return new Promise((resolve, reject)=>{
if($rootRouter._currentInstruction){
resolve( $rootRouter.recognize($rootRouter._currentInstruction.urlPath).then(function (data) {
return data.component.componentType;
}));
} else{
reject(null);
})
}
Now you can check resolve and reject with then() function,
factory.getCurrentComponent().then(function (resolved) {
//handle success here
}, function(rejected) {
// handle rejection here
});
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise

Mocking asynchronous requests within react's getInitialState

When i created this question, my doubt was about how would i be able to test an asynchronous request utilizing mocha/enzyme/chai/sinon.
I am sure that there are different ways, but a possible one is to mock it with a handmade function that returns the appropriate values (check the answer for details).
My getInitialState method is this:
getInitialState: function() {
var me = this;
var documentData = null;
var promise = me.getDocuments();
promise.then(function(value) {
var documents = value.map(function(obj) {
return Object.keys(obj).sort().map(function(key) {
return obj[key];
});
});
documentData = documents;
});
return ({
cd: false
});
},
And the getDocuments() function that returns a promise is this:
getDocuments: function() {
var deferred = when.defer();
Collection.fetch({cd: workspaceInfo.getCD()}).then(
function(results) {
deferred.resolve(results);
},
deferred.reject
);
return deferred.promise;
},
How can i successfuly test it?
Would i have to mock the getInitialState method itself? (is that even possible)
Or just the getDocuments function with some predictable return values?
Thanks in advance, any help will be appreciated.
I solved this by requiring the Collection (which is a rest API that brings some values from a database)
var Collection = require("path/to/my/collection/Collection");
Afterwards, i use it in my getDefaultProps() method:
getDefaultProps() {
return {
Collection: new Collection()
};
},
And this in turn enables me to write tests that initialize a mocked Collection (fileDataResponse is a JSON with some data):
var CollectionMock= {
fetch: () => {
return {
then: callback => callback(fileDataResponse)
};
}
};
And use it in my test afterwards:
it("should open the modal without a loaded configuration", function() {
var instance, wrapper;
wrapper = mount(
<DocumentPreview
Collection={CollectionMock}/>
);
instance = wrapper.component.getInstance();
instance.openModal();
expect(wrapper.find('#MockedTest' + 'docOid251085').exists()).to.equal(true);
wrapper.unmount();
});

Angular "Cannot read property 'then' of undefined" with promise

I am stuck on why my promises aren't working. From the other articles I have looked at, I think I am doing it correctly. Here is the code I have currently:
Factory code
factory.isLoggedIn = function() {
$http.get('/api/v1/fitbit/auth')
.success((data) => {
return data.status;
})
.error((error) => {
console.log('Error: ' + error);
});
}
Controller code
$scope.fitbitAuth = function() {
FitbitFactory.isLoggedIn()
.then(
function(data) {
$scope.fitbitStatus = data;
},
function(errorData) {
console.log(errorData);
});
return $scope.fitbitStatus;
};
From my understanding of promises, the return $scope.fitbitStatus should be populating the $scope.fitbitAuth, but it isn't. I am also returning a boolean in the Factory, which should be populating $scope.fitbitStatus.
You have to return something (the promise), or it is undefined.
Factory code:
factory.isLoggedIn = function() {
return $http.get('/api/v1/fitbit/auth');
}
Controller code:
$scope.fitbitAuth = function() {
return FitbitFactory.isLoggedIn()
.then(
function(data) {
$scope.fitbitStatus = data;
},
function(errorData) {
console.log(errorData);
});
};
The complete success/error block in your factory is not necessary and should be removed. I'm also unsure why you return $scope.fitbitStatus; as it is undefined at the time of return.
Edit: Edited the answer to actually return the promise.
Currently you haven't return anything from isLoggedIn factory method and you are calling .then method over it.
To make it working return $http promiseobject from service method. In your case you could simply return$http.getmethod call which return promise object itself and then you can easily chain them up by callingFitbitFactory.isLoggedIn().then`
factory.isLoggedIn = function() {
return $http.get('/api/v1/fitbit/auth');
}

Cancel pending API calls in Restangular

I have API service:
var SearchSuggestionApi = function (Restangular) {
return {
getSuggestion: function (keyword) {
return Restangular.one('search').customGET(null, {keyword:keyword});
}
};
};
SearchSuggestionApi.$inject = [
'Restangular'
];
I have controller to call this API:
vm.getSuggestion = function (keyword) {
SearchSuggestionApi.getSuggestion(keyword)
.then(
function (data) {
vm.listData = data;
}, function (error) {
console.log(error);
});
};
My problem is when I call vm.getSuggestion(keyword) two or many time (must call than one time). Such as:
vm.getSuggestion('a'); // => Return a array with many object in this
vm.getSuggestion('a b');// => Return empty array
Because vm.getSuggestion('a') return many data, it will finish after vm.getSuggestion('a b'). So vm.listData is [{object1}, {object2}, ...], but I want to vm.listData is [] (response data of the last function).
How can to cancel pending API call in first function when I call seconds function or another ways to get the last response data and set for vm.listData.
I researched some articles about cancel pending API calls, but it not help me about my problem.
Thanks for your help :)
There are various ways of solving this:
You can simply check in your then callback whether the value received is still current:
vm.getSuggestion = function (keyword) {
SearchSuggestionApi.getSuggestion(keyword)
.then(
function (data) {
if (vm.keyword === keyword) {
vm.listData = data;
}
}, function (error) {
console.log(error);
});
};
You can cancel the request by specifying a timeout promise
If you are solving this problem often, you might wish to replace the promise by an RxJS observable stream with the appropriate operators. This is the cleanest solution, but does require an additional library.

Jasmine, Parse.com&Promises: Testing functions that call query.get/find

I'm trying to get my head around testing a parse.com backed data service, but have not found a satisfying solution so far. Basically, I want to use karma/jasmine to test a function returning a promise.
I'm spying on the query.get() method to intercept and return an object that was created in the implementation of the jasmine spec. However, when the spy returns the local object, the success path of the query.get options argument is not executed. Instead, the to-be-tested function directly returns the unresolved promise, which is not what I want. Basically, I want to test the success path (and the error path) of the data service.
Here's the code:
to-be-tested parse.com data services
angular.module('app.services',[])
.factory('AppServices',function(){
var doFunction1 = function(){
var promise = new Parse.Promise();
var ParseObjectClass = Parse.Object.extend('ParseObject');
var query = new Parse.Query(ParseObjectClass);
query.get('abc1234',{
success: function(result){
promise.resolve(result);
},
error: function(result, error){
promise.reject(error);
}
});
return promise;
}
return {
function1: doFunction1
}
});
jasmine spec
describe('MyServices Tests', function() {
var AppServices;
var scope;
beforeEach(function() {
module('app.services');
});
beforeEach(inject(function($rootScope, AppServices) {
AppServices = AppServices;
scope = $rootScope.$new();
Parse.initialize("key1", "key2");
var user = new Parse.User({
id: 'abc1234',
});
var ParseObjectClass = Parse.Object.extend('ParseObject');
var obj1 = new ParseObjectClass({
id: 'xyc789'
});
spyOn(Parse.Query.prototype, 'get')
.and.callFake(function(options) {
return Parse.Promise.as(obj1);
});
}));
it('parseMockTest', function() {
var result = AppServices.function1(2);
console.log(JSON.stringify(result));
});
});
This is the result from the karma log:
LOG: '{"_resolved":false,"_rejected":false,"_resolvedCallbacks":[],"_rejectedCallbacks":[]}'
I would have expected that the returned promise is resolved.
Any ideas/hints on how to test functions that return promises?

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