AngularJS Informer service

Question

I'm using Twitter Bootstrap for UI in my webapp. Particulary its Alert component. I want to write a simple angular service to wrap Bootstrap's Alert to have a possibility of informing users from any peace of angular code. Like this:

Informer.inform("message", "ERROR"); // will result in alerting with `alert-error` class
Informer.inform("message", "INFO"); // will result in alerting with `alert-info` class

My idea is to to append the template to the end of the <body>:

<div class="alert {{alertClass}} fade in informer" id="informer">
    <button type="button" class="close" data-dismiss="alert">×</button>
    <div class="valignCenterWrapper">
        <div class="valignCenter" id="informerMessage">
            {{message}}
        </div>
    </div>
</div>

Something like this:

grfx.factory("Informer", function() {
    return {
        inform : function(message, type) {
            // Here be dragons. How can I compile/append the template.

            $("#inform").alert();
        }
    };
});

The only thing I want to know: how do I write this with angular, not with jQuery? Is the code above good for start? Folks in the internets say that I should only use directives for DOM manipulation. But I do not understand it: I do not have any existing markup to apply directive on it. Alerts will be appended to the page as a result of some compupations/user interactions. Which services ($compile, $parse, $document) should I use to compile temlate and append it somewhere to the body?

EDIT: Is it also possible to get angularjs service outside of controller. Just in regular JS code so I can write getServiece("Informer").inform("", "")?

EDIT 2: Ok, what I have now:

grfx.factory("Informer", function($compile, $rootScope) {
    return {
        inform : function(message, type) {
            var scope = $rootScope.$new();

            scope.message = message;
            scope.type = type;

            $(document.body).append($compile("<div class='alert {{type}} fade in informer' id='informer'><button type='button' class='close' data-dismiss='alert'>×</button><div class='valignCenterWrapper'><div class='valignCenter' id='informerMessage'>{{message}}</div></div></div>")(scope));
        }
    };
});

With this code I am able to use injected service from controllers. But there is an issue when I try to call service outside angular code:

angular.element(document).injector().get("Informer").inform("Message", "alert-error");

This shows popup with {{message}} e.g. it does not compile template correctly.

score 8 · Accepted Answer · answered Feb 11 '13 at 10:16

In AngularJS we should be focusing on model manipulation and your Informer service is no exception - it should only hold model and shouldn't be concerned with DOM manipulation. The rule of thumb where DOM manipulation = directive is a very good one and if you follow it it will save you a lot of headaches.

Back to your problem at hand, the solution is to have a service focused on model manipulation and a directive to display this model. Let's start with the service:

app.factory('Informer', function(){

  var messages = [];  
  var Informer = {};

  Informer.inform = function(msg, type) {
    messages.push({
      msg: msg,
      type: type
    });
  };

  Informer.allInfos = function() {
    return messages;
  };

  Informer.remove = function(info) {
    messages.splice(messages.indexOf(info), 1);
  };  

  return Informer;
});

When this service is ready you can easily use it in a controller (or even inside other services!):

app.controller('MainCtrl', function($scope, Informer) {

  Informer.inform("error message", "error");
  Informer.inform("info message", "info");

  $scope.allInfos = Informer.allInfos;  
  $scope.remove = Informer.remove;
});

And finally, to render alerts you can use bootstrap's markup directly, or write a very simple directive that encapsulates it. Here I', using the alert directive from http://angular-ui.github.com/bootstrap/

<body ng-controller="MainCtrl">
    <alert ng-repeat="alert in allInfos()" type="alert.type" close="remove(alert)">{{alert.msg}}</alert>
  </body>

Of course you don't need to use directives from this repo, you can create your own or use raw markup if needed.

Here is a plunker demonstrating a working example: http://plnkr.co/edit/VxAcjHFhxXODFB5iAfyX?p=preview

To sum up:

As a rule of thumb don't do DOM manipulation outside of directives
Service dealing with the model should be decoupled from model's presentation

I would also advice removing jQuery from a project while learning AngularJS. This way you will quicker get into AngularJS-zen state!

Thank you for the answer! I'll try your code. Cannot say I got it. Actually, **I am removing** jQuery from the project, but there is a lot of it, so I need them work together for some time. Also, can you please see my Edit 2, and suggest something for using service outside of angular? — madhead, Feb 11 '13 at 11:11
@madhead you really, really should remove any DOM manipulation logic from your service. Also, there is no point in using `$compile`. Just do model manipulation in your service and DOM manipulation in your template / directive. — pkozlowski.opensource, Feb 11 '13 at 11:17
Ok, I see you code works like a charm. Is there any possibility to use it outside of angular? In existing JS/jQuery callback, for example? Or inside custom `` (generated on server in some cases) tag on page? — madhead, Feb 11 '13 at 11:54

score 3 · Answer 2 · answered Feb 11 '13 at 09:31

Angular way, I believe, is to manipulate dom by hand as few as possible. And even if you have to manipulate it - do it only within a directive.

So, the way to go, unlike jQuery, is to have a model and use bindings to change your dom.

For that reason, the way I would choose - it to have some InformerController which is binded somewhere in your layout template, and iterate over an array of current informs, and draw them directly.

app.controller('InformersController', function($scope, InformerService) {
    $scope.informs = InformerService.get();
    $scope.close = function (index) {
          InformerService.close(index)
    }
});

And in your template:

<div ng-controller="InformersController">
     <div ng-repeat="inform in informs">
         <div class="alert {{inform.alertClass}} fade in informer">
            <button type="button" ng-click="close($index)" class="close">×</button>
            <div class="valignCenterWrapper">
                <div class="valignCenter">
                    {{inform.message}}
                </div>
            </div>
        </div>
     </div>
 </div>

If you need to show some alert from any place, use it injecting InformerService to your controller, and adding data using it.

app.service('InformerService', function () {

    var informs = [];
    this.get = function () {
        return informs;   
    };
    this.inform = function (message, type) {
        informs.push({
            alertClass: 'alert-' + type,
            message: message
        });
    }
    this.close = function (index) {
       informs.splice(index, 1);
    }

});

For example:

app.controller('SomeController', function($scope, InformerService) {
    $scope.doError = function (msg, type) {
        InformerService.inform(msg, type);
    };
});

And in your template:

<div class="well" ng-controller="SomeController">
    <button class="btn btn-danger" ng-click="doError('Hello', 'error')">Error</button>  
    <button class="btn btn-info" ng-click="doError('Hello', 'info')">Info</button>  
</div>

You can see it all together at this fiddle: http://jsfiddle.net/zc3YH/6/

Thank you for the answer! Seems like you with pkozlowski.opensource think almost in the same way. :) As I understood, I need some predefined markup on every page (yeah, my app is not angular-one-page-app) to use informer on it? What about using it outside of angular? In existing jQuery code? — madhead, Feb 11 '13 at 11:18

AngularJS Informer service

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