Calling `$q.when` takes a promise or any other type, if it is not a promise then it will wrap it in a promise and call resolve. If you pass a value to it then it is never going to be rejected.

From [the docs](https://docs.angularjs.org/api/ng/service/$q#when):

&gt;    Wraps an object that might be a value or a (3rd party) then-able promise into a $q promise.  This is useful when you are dealing with an object that might or might not be a promise, or if the promise comes from a source that can&#39;t be trusted.

I had to change the version of my npm app from 0.1 to 0.0.1 in order for npm not to do this. 

    $ npm install
    npm ERR! install Couldn&#39;t read dependencies
    npm ERR! Error: invalid version: 0.1
    npm ERR!     at validVersion (/usr/local/Cellar/node/0.10.5/lib/node_modules/npm/node_modul
    es/read-package-json/read-json.js:571:40)
    npm ERR!     at final (/usr/local/Cellar/node/0.10.5/lib/node_modules/npm/node_modules/read
    -package-json/read-json.js:323:23)
    npm ERR!     at /usr/local/Cellar/node/0.10.5/lib/node_modules/npm/node_modules/read-packag
    e-json/read-json.js:139:33
    npm ERR!     at cb (/usr/local/Cellar/node/0.10.5/lib/node_modules/npm/node_modules/slide/l
    ib/async-map.js:48:11)
    npm ERR!     at /usr/local/Cellar/node/0.10.5/lib/node_modules/npm/node_modules/read-packag
    e-json/read-json.js:301:48
    npm ERR!     at fs.js:207:20
    npm ERR!     at Object.oncomplete (fs.js:107:15)
    npm ERR! If you need help, you may report this log at:
    npm ERR!     &lt;http://github.com/isaacs/npm/issues&gt;
    npm ERR! or email it to:
    npm ERR!     &lt;npm-@googlegroups.com&gt;
    
    npm ERR! System Darwin 12.3.0
    npm ERR! command &quot;/usr/local/Cellar/node/0.10.5/bin/node&quot; &quot;/usr/local/bin/npm&quot; &quot;install&quot;
    npm ERR! cwd /Users/lust/Documents/ply/dev-server
    npm ERR! node -v v0.10.5
    npm ERR! npm -v 1.2.18
    npm ERR!
    npm ERR! Additional logging details can be found in:
    npm ERR!     /Users/lust/Documents/ply/dev-server/npm-debug.log
    npm ERR! not ok code 0

For completeness here&#39;s the working json

    $ cat package.json
    {
        &quot;name&quot;: &quot;ply&quot;,
        &quot;description&quot;: &quot;ply server for local dev testing deployments&quot;,
        &quot;version&quot;: &quot;0.0.1&quot;,
        &quot;private&quot;: true,
        &quot;dependencies&quot;: {
            &quot;express&quot;: &quot;3.x&quot;
        }
    } 

version used to be &quot;0.1&quot; when it made the error.

Is this some sort of API/ABI compatibility versioning concept requiring 3 sets of version numbers? Why is the error message not more friendly w.r.t. this?

npm: Why is a version &quot;0.1&quot; invalid?

In my app a User can create a Business. When they trigger the `index` action in my `BusinessesController` I want to check if a Business is related to the `current_user.id`:

- If yes: display the business. 
- If no: redirect to the ` new ` action. 

I was trying to use this:

    if Business.where(:user_id =&gt; current_user.id) == nil
      # no business found
    end

But it always returns true even when the business doesn&#39;t exist...

**How can I test if a record exists in my database?**

Check if record exists from controller in Rails

Can some one explain me how does `$q.when` work in AngularJS?
I&#39;m trying to analyse how `$http` work and found this:

    var promise = $q.when(config);

And here is config object from Chrome console:

    Object {transformRequest: Array[1], transformResponse: Array[1], cache: Object, method: &quot;GET&quot;, url: &quot;/schedule/month_index.html&quot;…}
    cache: Object
    headers: Object
    method: &quot;GET&quot;
    transformRequest: Array[1]
    transformResponse: Array[1]
    url: &quot;/schedule/month_index.html&quot;
    __proto__: Object

What happens next? How this object get&#39;s resolved or rejected?

How does Angular $q.when work?

Can some one explain me how does <code>$q.when</code> work in AngularJS?
I'm trying to analyse how <code>$http</code> work and found this:
<pre><code class="hljs language-ini">var promise = $q.when(config);
</code></pre>
And here is config object from Chrome console:
<pre><code class="hljs language-vbnet">Object {transformRequest: Array[1], transformResponse: Array[1], cache: Object, method: "GET", url: "/schedule/month_index.html"…}
cache: Object
headers: Object
method: "GET"
transformRequest: Array[1]
transformResponse: Array[1]
url: "/schedule/month_index.html"
__proto__: Object
</code></pre>
What happens next? How this object get's resolved or rejected?

I&#39;m using the [angular-seed](https://github.com/angular/angular-seed) template to structure my application. Initially I put all my JavaScript code into a single file, `main.js`. This file contained my module declaration, controllers, directives, filters, and services. The application works fine like this, but I&#39;m worried about scalability and maintainability as my application becomes more complex. I noticed that the angular-seed template has separate files for each of these, so I&#39;ve attempted to distribute my code from the single `main.js` file into each of the other files mentioned in the title to this question and found in the `app/js` directory of the [angular-seed](https://github.com/angular/angular-seed/tree/master/app/js) template.

My question is: how do I manage the dependencies to get the application to work? The existing documentation found [here](http://docs.angularjs.org/guide) isn&#39;t very clear in this regard since each of the examples given shows a single JavaScript source file.

An example of what I have is:


### app.js ###

    angular.module(&#39;myApp&#39;, 
        [&#39;myApp.filters&#39;,
         &#39;myApp.services&#39;,
         &#39;myApp.controllers&#39;]);

### controllers.js ###

    angular.module(&#39;myApp.controllers&#39;, []).
        controller(&#39;AppCtrl&#39;, [function ($scope, $http, $filter, MyService) {
    
            $scope.myService = MyService; // found in services.js
    
            // other functions...
        }
    ]);


### filters.js ###

    angular.module(&#39;myApp.filters&#39;, []).
        filter(&#39;myFilter&#39;, [function (MyService) {
            return function(value) {
                if (MyService.data) { // test to ensure service is loaded
                    for (var i = 0; i &lt; MyService.data.length; i++) {
                        // code to return appropriate value from MyService
                    }
                }
            }
        }]
    );

### services.js ###

    angular.module(&#39;myApp.services&#39;, []).
        factory(&#39;MyService&#39;, function($http) {
            var MyService = {};
            $http.get(&#39;resources/data.json&#39;).success(function(response) {
                MyService.data = response;
            });
            return MyService;
        }
    );

### main.js ###

    /* This is the single file I want to separate into the others */
    var myApp = angular.module(&#39;myApp&#39;), []);
    
    myApp.factory(&#39;MyService&#39;, function($http) {
        // same code as in services.js
    }
    
    myApp.filter(&#39;myFilter&#39;, function(MyService) {
        // same code as in filters.js
    }
    
    function AppCtrl ($scope, $http, $filter, MyService) {
        // same code as in app.js
    }

How do I manage the dependencies?

Thanks in advance.

AngularJS seed: putting JavaScript into separate files (app.js, controllers.js, directives.js, filters.js, services.js)

Using angular-ui-router, How can I use the [otherwise method][1] on [$stateProvider][2] or how can I use it at all ? 


  [1]: http://docs.angularjs.org/api/ng.$routeProvider
  [2]: https://github.com/angular-ui/ui-router/wiki

Otherwise on StateProvider

Simple question:  How can I set a scope value in html, to be read by my controller? 


    

&lt;!-- begin snippet: js hide: false console: true babel: false --&gt;

&lt;!-- language: lang-js --&gt;

    var app = angular.module(&#39;app&#39;, []);

    app.controller(&#39;MyController&#39;, function($scope) {
      console.log($scope.myVar);
    });

&lt;!-- language: lang-html --&gt;

    &lt;script src=&quot;https://ajax.googleapis.com/ajax/libs/angularjs/1.2.23/angular.min.js&quot;&gt;&lt;/script&gt;
    &lt;div ng-app=&#39;app&#39;&gt;
      &lt;div ng-controller=&quot;MyController&quot; app-myVar=&quot;test&quot;&gt;
        {{myVar}}
      &lt;/div&gt;
    &lt;/div&gt;

&lt;!-- end snippet --&gt;

JSFiddle:  http://jsfiddle.net/ncapito/YdQcX/



Set angular scope variable in markup

What is the difference between these two extend functions? 

&lt;!-- language: lang-js --&gt;

      angular.extend(a,b);
      $.extend(a,b);

While the jquery.extend is well documented the angular.extend lacks details and the comments there provide no answers. (https://docs.angularjs.org/api/ng/function/angular.extend).

Does angular.extend also provide deep copy?

jquery extend vs angular extend

I have an application with a complex layout where the user could put (drag/drop) widgets (by choosing from a predefined set of 100+ widgets) where every widget is a custom implementation that displays a set of data (fetched using REST call) in a specific way. I&#39;ve read tons of blog posts, stackoverflow questions and the official AngularJS docs but I cannot figure out how should I design my application to handle there requirements. Looking at demo apps, there is a single module (ng-app) and when constructing it in the .js file the dependent modules are declared as its dependencies, however i have a big set of widgets and somehow it&#39;s not advisable to describe them all there. I need suggession for the following questions:

* How should I design my app and widgets - should i have a separate AngularJS module or each widget should be a directive to the main module?
* If I design my widget as directives, is there a way to define dependency within a directive. I.e. to say that my directive uses ng-calender in its implementation?
* If I design each widget as a separate module, is there a way to dynamically add the widget module as a dependency to the main module?
* How should I design the controllers - one controller per widget probably?
* How should i separate the state (scope) if i have multiple widgets from the same type in the view?
* Are there bestpractices for designing reusable widgets with AngularJS?

**EDIT**

Useful references:

 - [ocLazyLoad - great lazy loading lib for AngularJS][1]
 - [Seed project - modules + lazy loading on route change (ES6, systemjs, ocLazyLoad)][2]
 - [Lazy loading in AngularJS][3]
 - [Dynamically Loading Controllers and Views with AngularJS and RequireJS][4]
 - [Loading AngularJS Components With RequireJS After Application Bootstrap][5]
 - [Demo project about lazy loading of AngularJS resources on GitHub][6]
 - [Load On Demand project][7]
 - [Inject module dynamically only if required][8]
 - [Another lazy loading in Angular article][9]
 - [Code Organization in Large AngularJS and JavaScript Applications][10]


  [1]: https://github.com/ocombe/ocLazyLoad
  [2]: https://github.com/lookfirst/systemjs-seed
  [3]: http://ify.io/lazy-loading-in-angularjs/
  [4]: http://weblogs.asp.net/dwahlin/archive/2013/05/22/dynamically-loading-controllers-and-views-with-angularjs-and-requirejs.aspx
  [5]: http://www.bennadel.com/blog/2554-Loading-AngularJS-Components-With-RequireJS-After-Application-Bootstrap.htm
  [6]: https://github.com/nikospara/angular-require-lazy
  [7]: https://github.com/AndyGrom/loadOnDemand
  [8]: https://stackoverflow.com/questions/18591966/inject-module-dynamically-only-if-required
  [9]: http://roubenmeschian.com/rubo/?p=40
  [10]: http://cliffmeyers.com/blog/2013/4/21/code-organization-angularjs-javascript

Developing an AngularJS app with dynamic set of modules

I want to return an error from a function if it panics (in Go):

    func getReport(filename string) (rep report, err error) {
    	rep.data = make(map[string]float64)

    	defer func() {
    		if r := recover(); r != nil {
    			fmt.Println(&quot;Recovered in f&quot;, r)
    			err, _ = r.(error)
                return nil, err
			}
    	}()
    	panic(&quot;Report format not recognized.&quot;)
        // rest of the getReport function, which can try to out-of-bound-access a slice
        ...
    } 


I appear to have misunderstood the very concept of panic and defer. Can anybody enlighten me?


Go: returning from defer

I want to have a for-loop which calls async functions each iteration.

After the for-loop I want to execute another code block, but not before all the previous calls in the for-loop have been resolved.

My problem at the moment is, that either the code-block after the for-loop is executed before all async calls have finished OR it is not executed at all.

The code part with the FOR-loop and the code block after it (for complete code, please see [fiddle][1]):

    [..]
    function outerFunction($q, $scope) {
        var defer = $q.defer();    
        readSome($q,$scope).then(function() {
            var promise = writeSome($q, $scope.testArray[0])
            for (var i=1; i &lt; $scope.testArray.length; i++) {
                 promise = promise.then(
                     angular.bind(null, writeSome, $q, $scope.testArray[i])
                 );                                  
            } 
            // this must not be called before all calls in for-loop have finished
            promise = promise.then(function() {
                return writeSome($q, &quot;finish&quot;).then(function() {
                    console.log(&quot;resolve&quot;);
                    // resolving here after everything has been done, yey!
                    defer.resolve();
                });   
            });        
        });   
   
        return defer.promise;
    }

I&#39;ve created a jsFiddle which can be found here [http://jsfiddle.net/riemersebastian/B43u6/3/][1]. 

At the moment it looks like the execution order is fine (see the console output).

My guess is, that this is simply because every function call returns immediately without doing any real work. I have tried to delay the defer.resolve with setTimeout but failed (i.e. the last code block was never executed). You can see it in the outcommented block in the fiddle. 

When I use the real functions which write to file and read from file, the last code block is executed before the last write operation finishes, which is not what I want.

Of course, the error could be in one of those read/write functions, but I would like to verify that there is nothing wrong with the code I have posted here.


  [1]: http://jsfiddle.net/riemersebastian/B43u6/4/

angular $q, How to chain multiple promises within and after a for-loop

I need to use `defer` to free allocations manually created using `C` library, but I also need to `os.Exit` with non 0 status at some point. The tricky part is that `os.Exit` skips any deferred instruction:

    package main
    
    import &quot;fmt&quot;
    import &quot;os&quot;
    
    func main() {
    
        // `defer`s will _not_ be run when using `os.Exit`, so
        // this `fmt.Println` will never be called.
        defer fmt.Println(&quot;!&quot;)
        // sometimes ones might use defer to do critical operations
        // like close a database, remove a lock or free memory
    
        // Exit with status code.
        os.Exit(3)
    }

Playground: http://play.golang.org/p/CDiAh9SXRM stolen from https://gobyexample.com/exit

So how to exit a go program honoring declared `defer` calls? Is there any alternative to `os.Exit`?

How to exit a go program honoring deferred calls?

What would be the idiomatic way to do something like a while loop with promises. So:

do something
if the condition still stands do it again
repeat
then do something else.

    dosomething.then(possilblydomoresomethings).then(finish)

I&#39;ve done it this way I was wondering if there were any better/more idomatic ways?

    var q = require(&#39;q&#39;);
    
    var index = 1;
    
    var useless =  function(){
            var currentIndex = index;
            console.log(currentIndex)
            var deferred = q.defer();
            setTimeout(function(){
                if(currentIndex &gt; 10)
                    deferred.resolve(false);
                else deferred.resolve(true);
                },500);
            return deferred.promise;
        }
    
    var control = function(cont){
            var deferred = q.defer();
            if(cont){
                    index = index + 1;
                    useless().then(control).then(function(){
                            deferred.resolve();
                        });
                }
             else deferred.resolve();
            return deferred.promise;
        }
    
    var chain = useless().then(control).then(function(){console.log(&#39;done&#39;)});

Output:
1
2
3
4
5
6
7
8
9
10
11
done

While loop with promises

I understand that typically one would just attach continuation code with a `then()` call and chain behaviour when using promises. 

However, I want to kick off a promise-wrapped asynchronous call and then separately kick off a 3-second `$timeout()` so I can take a UI action, ONLY IF the original promise has not yet completed.  (I anticipate that this would only happen on slow connections, mobile devices on 3G, etc.)

Given a promise, can I check whether it&#39;s complete or not without blocking or waiting?

How to Check Whether an Angular $q promise Is Resolved

I have implemented the $q.all in angularjs, but I can not make the code work. Here is my code :


    UploadService.uploadQuestion = function(questions){

			var promises = [];

			for(var i = 0 ; i &lt; questions.length ; i++){

				var deffered  = $q.defer();
				var question  = questions[i]; 
			
				$http({

					url   : &#39;upload/question&#39;,
					method: &#39;POST&#39;,
					data  : question
				}).
				success(function(data){
					deffered.resolve(data);
				}).
				error(function(error){
					deffered.reject();
				});

				promises.push(deffered.promise);
			}
			
			return $q.all(promises);
		}


And here is my controller which call the services:
    
    uploadService.uploadQuestion(questions).then(function(datas){
          
       //the datas can not be retrieved although the server has responded    
    }, 
    function(errors){ 
       //errors can not be retrieved also
        
    })

I think there is some problem setting up $q.all in my service.

																						    

Angularjs $q.all

I&#39;ve been developing JavaScript for a few years and I don&#39;t understand the fuss about promises at all.

It seems like all I do is change:

    api(function(result){
        api2(function(result2){
            api3(function(result3){
                 // do work
            });
        });
    });

Which I could use a library like [async](https://github.com/caolan/async) for anyway, with something like:

    api().then(function(result){
         api2().then(function(result2){
              api3().then(function(result3){
                   // do work
              });
         });
    });

Which is more code and less readable. I didn&#39;t gain anything here, it&#39;s not suddenly magically &#39;flat&#39; either. Not to mention having to convert things to promises.

So, what&#39;s the big fuss about promises here?

Aren&#39;t promises just callbacks?

I have a javascript function where I want to return the value that I get after the return method.
Easier to see than explain

    function getValue(file){
        var val;
        lookupValue(file).then(function(res){
           val = res.val;
        }
        return val;
    }

What is the best way to do this with a promise. As I understand it, the `return val` will return before the lookupValue has done it&#39;s then, but the I can&#39;t `return res.val` as that is only returning from the inner function. 

Content Type	Original Author	Original Content on Stackoverflow
Question	SET	View Question on Stackoverflow
Solution 1 - Angularjs	Derek Ekins	View Answer on Stackoverflow

How does Angular $q.when work?

Angularjs Problem Overview

Angularjs Solutions

Solution 1 - Angularjs

Check if record exists from controller in Rails

npm: Why is a version "0.1" invalid?

Attributions