`$scope.itemarray.length = 0;`  &lt;&lt; this is correct. Length is read-write property.

`$scope.itemarray = [];` &lt;&lt; this creates new empty array. If you have bindings to old itemarray, they may be lost. (Html binding like `ng-if=&quot;itemarray[0]&quot;` wont be lost)

I registered a service worker successfully, but then the code

    navigator.serviceWorker.ready.then(function(serviceWorkerRegistration) {
        // Do we already have a push message subscription?
        ....

hangs -- the function is never called. Why?

navigator.serviceWorker is never ready

I&#39;ve been playing around with arrays of generic classes with different types. It&#39;s easiest to explain my problem with some sample code:

    // Obviously a very pointless protocol...
    protocol MyProtocol {
        var value: Self { get }
    }
    
    extension Int   : MyProtocol {  var value: Int    { return self } }
    extension Double: MyProtocol {  var value: Double { return self } }
    
    class Container&lt;T: MyProtocol&gt; {
        var values: [T]
        
        init(_ values: T...) {
            self.values = values
        }
   
        func myMethod() -&gt; [T] {
            return values
        }
    }
   

Now if I try to create an array of containers like so:

    var containers: [Container&lt;MyProtocol&gt;] = []

I get the error:

&gt; Protocol &#39;MyProtocol&#39; can only be used as a generic constraint because it has Self or associated type requirements.

To fix this I can use `[AnyObject]`:

    let containers: [AnyObject] = [Container&lt;Int&gt;(1, 2, 3), Container&lt;Double&gt;(1.0, 2.0, 3.0)]
    // Explicitly stating the types just for clarity.

But now another &#39;problem&#39; emerges when enumerating through `containers`:

    for container in containers {
        if let c = container as? Container&lt;Int&gt; {
            println(c.myMethod())
        
        } else if let c = container as? Container&lt;Double&gt; {
            println(c.myMethod())
        }
    }

As you can see in the code above, after determining the type of `container` the same method is called in both cases. My question is: 

**Is there a better way to get the `Container` with the correct type than casting to every possible type of `Container`? Or is there something else I&#39;ve overlooked?**

Arrays of Generics in Swift

     $scope.itemarray = [&#39;A&#39;, &#39;B&#39;, &#39;C&#39;];  

this will clear the array but the ui wont be updated.

    $scope.itemarray = [];


this works fine! why?

     $scope.itemarray.length = 0;  

How to clear an angularJS array

<pre><code class="hljs language-ini"> $scope.itemarray = ['A', 'B', 'C']; 
</code></pre>
this will clear the array but the ui wont be updated.
<pre><code class="hljs language-ini">$scope.itemarray = [];
</code></pre>
this works fine! why?
<pre><code class="hljs language-ini"> $scope.itemarray.length = 0; 
</code></pre>

I want to read the onClick event value properties. But when I click on it, I see something like this on the console: 

    SyntheticMouseEvent {dispatchConfig: Object, dispatchMarker: &quot;.1.1.0.2.0.0:1&quot;, nativeEvent: MouseEvent, type: &quot;click&quot;, target

My code is working correctly. When I run I can see `{column}` but can&#39;t get it in the onClick event.

My Code:

    var HeaderRows = React.createClass({
      handleSort:  function(value) {
        console.log(value);
      },
      render: function () {
        var that = this;
        return(
          &lt;tr&gt;
            {this.props.defaultColumns.map(function (column) {
              return (
                &lt;th value={column} onClick={that.handleSort} &gt;{column}&lt;/th&gt;
              );
            })}
            {this.props.externalColumns.map(function (column) {
              // Multi dimension array - 0 is column name
              var externalColumnName = column[0];
              return ( &lt;th&gt;{externalColumnName}&lt;/th&gt;);
            })}
          &lt;/tr&gt;
        );
      }
    });


How can I pass a value to the `onClick` event in React js?

React js onClick can&#39;t pass value to method

Is there a way to write this on fewer lines, but still easily readable?

    var month = &#39;&#39;;

	switch(mm) {
		case &#39;1&#39;:
			month = &#39;January&#39;;
	        break;
	    case &#39;2&#39;:
	    	month = &#39;February&#39;;
	        break;
	    case &#39;3&#39;:
	    	month = &#39;March&#39;;
	    	break;
	    case &#39;4&#39;:
	    	month = &#39;April&#39;;
	        break;
	    case &#39;5&#39;:
	    	month = &#39;May&#39;;
	        break;
	    case &#39;6&#39;:
	    	month = &#39;June&#39;;
	        break;
	    case &#39;7&#39;:
	    	month = &#39;July&#39;;
	        break;
	    case &#39;8&#39;:
	    	month = &#39;August&#39;;
	        break;
	    case &#39;9&#39;:
	    	month = &#39;September&#39;;
	    	break;
	    case &#39;10&#39;:
	    	month = &#39;October&#39;;
	        break;
	    case &#39;11&#39;:
	    	month = &#39;November&#39;;
	        break;
	    case &#39;12&#39;:
	    	month = &#39;December&#39;;
	        break;
	}



How to shorten switch case block converting a number to a month name?

I need to sort an array of strings, but I need it so that null is always last. For example, the array:

    var arr = [a, b, null, d, null]

When sorted ascending I need it to be sorted like `[a, b, d, null, null]` and when sorted descending I need it to be sorted like `[d, b, a, null, null]`.

Is this possible? I tried the solution found below but it&#39;s not quite what I need.

https://stackoverflow.com/questions/19101573/how-can-one-compare-string-and-numeric-values-respecting-negative-values-with

Sort an array so that null values always come last

I&#39;m using react and react-router for my application on the client side. I can&#39;t seem to figure out how to get the following query parameters from a url like:

    http://xmen.database/search#/?status=APPROVED&amp;page=1&amp;limit=20

My routes look like this (the path is totally wrong I know):

    var routes = (
    &lt;Route&gt;
        &lt;DefaultRoute handler={SearchDisplay}/&gt;
        &lt;Route name=&quot;search&quot; path=&quot;?status=:status&amp;page=:page&amp;limit=:limit&quot; handler={SearchDisplay}/&gt;
        &lt;Route name=&quot;xmen&quot; path=&quot;candidate/:accountId&quot; handler={XmenDisplay}/&gt;
    &lt;/Route&gt;
    );

My route is working fine but I&#39;m just not sure how to format the path to get the parameters I want. Appreciate any help on this!

Getting query parameters from react-router hash fragment

I want create paging link for my grid.I pass maxPages(number) property to component but i cant use for in render method. What can i do ?

    var Pagination = React.createClass({

    render: function(){
      

        return(
        &lt;div class=&quot;text-center&quot;&gt;
            &lt;ul class=&quot;pagination&quot;&gt;

                &lt;li&gt;&lt;a href=&quot;#&quot;&gt;&#171;&lt;/a&gt;&lt;/li&gt;
                {for (var i=0;i &lt;10;i++;)
                {
                  return( &lt;li&gt;&lt;a href=&quot;#&quot;&gt;i + 1 &lt;/a&gt;&lt;/li&gt;);
                }
                }
             
                &lt;li&gt;&lt;a href=&quot;#&quot;&gt;&#187;&lt;/a&gt;&lt;/li&gt;
            &lt;/ul&gt;
        &lt;/div&gt;);

    }});

For loop in react render method

How can i change the current date to this format(DD/MM/YYYY) using moment.js?


I have tried below code.


 

    $scope.SearchDate = moment(new Date(), &quot;DD/MM/YYYY&quot;);


But it&#39;s return `0037-11-24T18:30:00.000Z`. Did&#39;t help to format current date. 






DD/MM/YYYY Date format in Moment.js

I was going through the `forEach` `loop` in `AngularJS`. There are few points that I did not understood about it.

1. What is the use of the iterator function? Is there any way to go without it?
2. What is the significance of the key and value as shown below?

`angular.forEach($scope.data, function(value, key){});`

**PS:** I tried to run this function without the arguments and it did not work.

Here&#39;s my `json`:

    [
       {
         &quot;Name&quot;: &quot;Thomas&quot;,
         &quot;Password&quot;: &quot;thomasTheKing&quot;
       },
       {
         &quot;Name&quot;: &quot;Linda&quot;,
         &quot;Password&quot;: &quot;lindatheQueen&quot;
       }
    ]

My `JavaScript` file: 

    var app = angular.module(&#39;testModule&#39;, []);

    app.controller(&#39;testController&#39;, function($scope, $http){
       $http.get(&#39;Data/info.json&#39;).then(
          function(data){
             $scope.data = data;
          }
       );

       angular.forEach($scope.data, function(value, key){
          if(value.Password == &quot;thomasTheKing&quot;)
             console.log(&quot;username is thomas&quot;);
       });
    });

**Another question**: Why the function above does not enter on if condition and print &quot;username is thomas&quot; in the console?

foreach loop in angularjs

I am working in an app where I need to keep some data during the user is logged in and I have that question, what is the difference among 
localStorage, sessionStorage, cookies ???

I was asking what can I use in order to persist some data in the DOM, even if the user refresh the page, some people says: use sessionStorage, or localStorage, then, someone came up with the idea of use [ngCookies](https://docs.angularjs.org/api/ngCookies/service/$cookies) because it works in every browser, but, which should I use ?

localStorage vs sessionStorage vs cookies

[JSfiddle](http://jsfiddle.net/wwno55hj/)

**Problem:**

I have a SELECT-element in my page, which is filled in with an `ng-repeat`. It also has a `ng-model` which has a default value.

When I change the value, the `ng-model` adapts, that&#39;s ok. But the dropdown-list shows an empty slot at launch, where it should have the item with the default value selected instead.


**Code**

    &lt;div ng-app ng-controller=&quot;myCtrl&quot;&gt;
        &lt;select class=&quot;form-control&quot; ng-change=&quot;unitChanged()&quot; ng-model=&quot;data.unit&quot;&gt;
             &lt;option ng-repeat=&quot;item in units&quot; ng-value=&quot;item.id&quot;&gt;{{item.label}}&lt;/option&gt;
        &lt;/select&gt;
    &lt;/div&gt;

With JS:

    function myCtrl ($scope) {
        $scope.units = [
            {&#39;id&#39;: 10, &#39;label&#39;: &#39;test1&#39;},
            {&#39;id&#39;: 27, &#39;label&#39;: &#39;test2&#39;},
            {&#39;id&#39;: 39, &#39;label&#39;: &#39;test3&#39;},
        ]
    
            $scope.data = {
            &#39;id&#39;: 1,
            &#39;unit&#39;: 27
            }
    
    };


AngularJs - ng-model in a SELECT

I load some binary data using 

    $http.post(url, data, { responseType: &quot;arraybuffer&quot; }).success(
                function (data) { /*  */ });

In case of an error, the server responds with an error JSON object like

    { &quot;message&quot; : &quot;something went wrong!&quot; }

Is there any way to get the error response in a different type than a success response?

    $http.post(url, data, { responseType: &quot;arraybuffer&quot; })
      .success(function (data) { /*  */ })
      .error(function (data) { /* how to access data.message ??? */ })

Content Type	Original Author	Original Content on Stackoverflow
Question	nullException	View Question on Stackoverflow
Solution 1 - Javascript	Petr Averyanov	View Answer on Stackoverflow

How to clear an angularJS array

Javascript Problem Overview

Javascript Solutions

Solution 1 - Javascript

Arrays of Generics in Swift

navigator.serviceWorker is never ready

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