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How to show a loading message before filter with AngularJS?

I need to show some "Loading Message" when a filter is about to happen with AngularJS. My filter is fast, so I can't just show it before return the filtered data. My code:
.filter('filterName', function () {
return function (pacotes, escopo) {
var filtered = [];
pacotes.forEach(function (pacote) {
if (condition)
filtered.push(pacote);
});
return filtered;
}
})
What can I do to show some message, div, anything, before return this data?

Somewhere in your html:
<p id="loadingMessage" ng-show="showMessage"></p>
Filter:
.filter('filterName', function () {
$scope.showMessage = true;
$timeout(return function (pacotes, escopo) {
var filtered = [];
pacotes.forEach(function (pacote) {
if (condition)
filtered.push(pacote);
});
$scope.showMessage = false;
return filtered;
}, 3000);
})
I was not able to test this since I don't have all of your code. But something like this should work assuming I have the syntax right. You would have to inject $scope and $timeout in the appropriate places for this to work though.
Edit: I just realized escopo likely means scope in another language. Assuming that is true and you are actually passing in the scope, just put escopo where I have $scope.

AngularJS: triggering the evaluation of bindings that include a filter

I am working on a project in which the client needs to be able to change each and any string that we've used in the application. This need is similar to i18n needs, except that what we, the dev team, provided and the set of strings that the client may end up with after their modifications are both in the same language.
I have therefore implemented a filter, so that strings in html views are written as an Angular expression such as {{'one.code.on.view1' | label }}. The filter relies on a service that "holds the entire set of labels in memory", so to speak.
I've designed a simple UI for users to modify text labels: all labels are shown in an angular-ui-grid. Each line has the (non-modifiable) code and the (modifiable) label. Using the grid's inline edit feature, I save the modified label to the database. So far, so good.
My problem is that when saving the modified label to the database, I also update the entry of that label in the service that "holds labels" but unfortunately, in case the modified label were displayed on screen, the old value isn't updated.
My question is: how can I trigger an evaluation of bindings on the view? I have used every $timeout or $apply trick I knew but to no avail, which isn't very surprising since all the code runs within Angular contexts.
Here is the code of the filter and service: (for the sake of clarity, "libellé" is the French word for "label" even though we sometimes improperly use "label"; and 'scoop' is the name of the project, hence its use as a prefix)
function scoopLabelSceFn($resource, $rootScope, $timeout) {
var rest = $resource('admin/libelle/list', {}, {});
var labels = [];
function loadAllLabels() {
labels = rest.query({}, function(result) {
var liste = [];
for (var idx = 0; idx < result.length; ++idx) {
var entry = result[idx];
liste[entry.code] = entry.libelle;
}
labels = liste;
});
}
loadAllLabels();
return {
getLabels : function() {
return labels;
},
reloadLabels : function() {
loadAllLabels();
},
updateLabel : function(code, newValue) {
labels[code] = newValue;
}
};
}
function scoopLabelFilterFn($log, scoopLabelService) {
return function(input) {
if (angular.isString(input)) {
var libelles = scoopLabelService.getLabels();
var res = libelles[input];
if (res) {
return res;
}
$log.log("scoopLabelFilter: no entry for: " + input);
return input;
}
$log.log("scoopLabelFilter: incorrect parameter type");
return "";
};
}
module.filter("label", [ "$log", "scoopLabelService", scoopLabelFilterFn ]);
module.factory("scoopLabelService", [ "$resource", "$rootScope", "$timeout", scoopLabelSceFn ]);

Actually, there is nothing conceptually wrong with the code.
The way Angular treats filters has apparently changed somewhere on the 1.3.x branch. As a consequence, the code returning the filter function has to be modified.
Old code:
return function(input) {
...
Modified code:
function filterFn(input) {
...
filterFn.$stateful = true;
return filterFn;
With this, all expressions related to the filter are automatically reevaluated.

angularFire 3 way data binding won't update an function

I have a firebaseObject (MyFirebaseService.getCurrentUser()) bind to $scope.user.
After binding successful, I loop tho the object to see if the object contain "associatedCourseId" equal to some value ($stateParams.id). If does, the $scope.finishLessonCount count up. The problem is, when I add new Object inside the firebaseObject (that bindto user) via other page OR inside firebase, the finishLessonCount value won't change as what I expect for 3 way binding. I need to refresh the page to see the finishLessonCount reflect the true value. What is wrong? I want the finishLessonCount change using the compare function as I add more finishedLessons into the firebaseObject. Please see code below:
MyFirebaseService.getCurrentUser().$bindTo($scope, "user").then(function(){
for (var key in $scope.user.finishedLessons) {
if ($scope.user.finishedLessons.hasOwnProperty(key)) {
if ($scope.user.finishedLessons[key].associatedCourseId == $stateParams.id) {
$scope.finishLessonCount++;
}
}
};
console.log ($scope.finishLessonCount);
});
UPDATE 1 according to #Kato solution:
I decide to use Extending firebaseOject way to solute this problem. But still, it does not. I did not use factory here to simplify thing since I need to pass in courseId to do the operation. Here is my code:
function countLessons(lessons, courseId) {
var count = 0;
for(var key in lessons) {
if( lessons[key].associatedCourseId == courseId) {
count++;
}
}
return count;
}
var UserWithLessonsCounter = $firebaseObject.$extend({
$$updated: function(snap) {
var changed = $firebaseObject.prototype.$$updated.call(this, snap);
this.lessonCount = countLessons(this.finishedLessons, $stateParams.id);
}
});
var refTemp = new Firebase($rootScope.baseUrl + "users/" + $rootScope.userId);
var userTemp = new UserWithLessonsCounter(refTemp);
userTemp.$bindTo($scope, "userTemp").then(function(){
console.log($scope.userTemp);
});
userTemp.$watch(function() {
console.log("Does this run at all? " + $scope.userTemp.lessonCount);
});
I update the user object, the lessonCount value did not change unless I refresh the page. And the console.log inside $watch did not run at all. What is wrong?

The promise returned by $bindTo is called exactly once. It's not an event listener. You can't listen to this to get updated each time there is a change.
Please read the guide, start to finish, and read about Angular's $watch method before continuing down this route, as with some fundamental knowledge, this should not have been your first instinct.
A beginner approach would be to utilize $watch:
MyFirebaseService.getCurrentUser().$bindTo($scope, "user");
$scope.$watch('user', function() {
for (var key in $scope.user.finishedLessons) {
if ($scope.user.finishedLessons.hasOwnProperty(key)) {
if ($scope.user.finishedLessons[key].associatedCourseId == $stateParams.id) {
$scope.finishLessonCount++;
}
}
};
console.log ($scope.finishLessonCount);
});
Or, having familiarized with the AngularFire API, one might pick $scope.user.$watch() in place of the scope method, which would prove more efficient.
Having written a large portion of the AngularFire code, I would pick the $extend tool, which was added precisely for use cases like this:
// making some assumptions here since you haven't included
// the code for your firebase service, which does not seem SOLID
app.factory('UserWithLessonsCounter', function($firebaseObject) {
return $firebaseObject.$extend({
$$updated: function(snap) {
var changed = $firebaseObject.prototype.$$updated.call(this, snap);
this.lessonCount = countLessons(this.finishedLessons);
return changed;
}
});
});
function countLessons(lessons) {
var count = 0;
for(var key in lessons) {
if( lessons.hasOwnProperty(key) ) {
count++;
}
}
return count;
}
And now in your controller:
app.controller('...', function($scope, UserWithLessonsCounter) {
var ref = new Firebase(...);
var user = new UserWithLessonCounter(ref);
user.$bindTo($scope, 'user');
user.$watch(function() {
console.log($scope.user.lessonCount);
});
});

Factory has two methods, one is $http method with $promise - how to reference the other method from within the first one's success function?

In one of my factories I need to set a variable when data is fetched (through $http) so I can access it in my controller (the intention is to display a spinner image until the data is loaded).
.factory('LoadData', function LoadData($http, $q){
return {
getMyData: function(){
return $http(
// implementation of the call
).then(
function(response){
var myData = response.data;
// this should be reference to the other method (getLoadStatus)
// where I want to change its value to "true"
// this doesn't work - "this" or "self" don't work either because we're in another function
LoadData.getLoadStatus.status = true;
}
);
},
// by calling the below method from my controller,
// I want to mark the completion of data fetching
getLoadStatus = function(){
var status = null;
return status;
}
}
}
I hope you got the idea - how could this be accomplished? Also, I'm open to any suggestions which are aimed towards a better approach (I want to pick up best practice whenever possible).

Status is essentially a private variable; use it as:
.factory('LoadData', function LoadData($http, $q){
var status = null; // ESSENTIALLY PRIVATE TO THE SERVICE
return {
getMyData: function(){
return $http(...).then(function(response){
...
status = true;
});
},
getLoadStatus = function(){
return status;
}
};
})

There are several ways.
Here's one which I prefer to use:
.factory('LoadData', function LoadData($http, $q){
var status = false;
var service = {
getMyData: getMyData,
status: status
};
return service;
function getMyData() {
return $http(
// implementation of the call
).then(
function(response){
var myData = response.data;
status = true;
}
);
}
}
This provides good encapsulation of your methods and gives you a clean interface to export. No need for the getter method if you don't want it.
Inspiration via John Papa's Angular style guide (found here).

You could simply store variable flag in closure:
.factory('LoadData', function LoadData($http, $q) {
var status = false;
return {
getMyData: function() {
status = false;
return $http(/* implementation of the call */).then(function(response) {
status = true;
return response.data;
});
},
getLoadStatus: function() {
return status;
}
}
});
Also if getMyData loads fresh data every time, it's important to reset status to false before each request.

I actually decide to use a promise in my controller after calling this service and when data is returned, I am simply making the status true. It seems that is best practice to have a promise returned when calling a service so I should be good.

Getting a Filter to handle a Promised Service

I have already started to rework this code to operate synchronously, but out of curiosity and a desire to support both means, I need some help understanding how to get a filter to jive with a promise. As some other posts mention a filter seems to just resolve to {} from a promise.
Basic Pattern
Here's a breakdown:
Define a service in the module that returns a promise instead of an object
module.factory('promisedSvc', ['$http', function($http) {
var httpPromise = null,
servicePromise = null,
service = {},
dataSet = {};
var httpPromise = $http.get('somedata.json').success(function(data) {
dataSet = data;
});
servicePromise = httpPromise.then(function(){
service.getData = function(key) {
return dataSet[key];
};
service.addData = function(key, value) {
dataSet[key] = value;
};
return service;
});
/*
In actuality I proxied the service methods onto the promise because
I didn't want consumers of the service to have to deal with it being
a promise. There is the caveat of setting properties on a class I
don't own (property collisions), a risk I'm okay taking, but YMMV
Commented out proxies
servicePromise.getData = function(key) {
return this.then(function(svc){
return svc.getData(key);
});
};
servicePromise.addData = function(key, value) {
this.then(function(svc){
svc.addData(key, value);
});
};
*/
return servicePromise;
}]);
Controllers can handle this promisedSvc fine, you just get the promise injected into the controller and then use the then function on the promise to wrap the setting of a $scope property to the function call on the eventual service object: getData(key) or setData(key, value). Alternately you can just treat it as normal if you proxied the functions onto the promise like in the commented out block.
Filters do not seem to inherently handle promises like $scope does. I am looking for a way to get the filter to inject the promisedSvc and be able to call getData(key) without it resolving to {} because the promise has not resolved yet. Below is an example of what does not work:
module.filter('svcData', ['promisedSvc', function(promisedSvc) {
return function(input) {
return promisedSvc.then(function(svc) {
var value = svc.getData(input);
return value;
});
};
}]);
So is there a way to write the filter to be able to resolve the value?
Use Case
That is the simplified pattern of what I am trying to achieve. For those curious, my actual use case is to pre-fetch i18n/l10n resource bundle information so I can localize all the text in my application. The pre-fetch could all be in the Javascript environment (attached to some already loaded global or in a provider), but we also have scenarios with database-stored Resource Bundles so I needed a version of code that can pre-fetch all the information from the server via AJAX.

It's not exactly what I'm looking for, but at least to document a workaround:
It's possible to use a function on the $scope instead of a filter.
module.factory('promisedSvc', ['$http', '$rootScope', function($http, $rootScope) {
var httpPromise = null,
servicePromise = null,
service = {},
dataSet = {};
var httpPromise = $http.get('somedata.json').success(function(data) {
dataSet = data;
});
servicePromise = httpPromise.then(function(){
service.getData = function(key) {
return dataSet[key];
};
service.addData = function(key, value) {
dataSet[key] = value;
};
//Here is the addition to setup the function on the rootScope
$rootScope.svcData = function(key) {
return service.getData(key);
};
return service;
});
return servicePromise;
}]);
And then in a template instead of {{ 'key1' | svcData }} you would use {{ svcData('key1') }}
I tested that if you delay the promises resolution (for example setup a wait in the $http.success) that the impact is the page loads, but the values from the svcData function will only populate into the template once the promises resolve.
Still would be nice to accomplish the same with a filter if possible.