It is possible. 

    &lt;span ng-if=&quot;checked &amp;&amp; checked2&quot;&gt;
      I&#39;m removed when the checkbox is unchecked.
    &lt;/span&gt;

http://plnkr.co/edit/UKNoaaJX5KG3J7AswhLV?p=preview

Just to clarify, be aware bracket placement is important!

These can be added to any HTML tags... span, div, table, p, tr, td etc.

**AngularJS**

    ng-if=&quot;check1 &amp;&amp; !check2&quot; -- AND NOT
    ng-if=&quot;check1 || check2&quot; -- OR
    ng-if=&quot;(check1 || check2) &amp;&amp; check3&quot; -- AND/OR - Make sure to use brackets

**Angular2**+

    *ngIf=&quot;check1 &amp;&amp; !check2&quot; -- AND NOT
    *ngIf=&quot;check1 || check2&quot; -- OR
    *ngIf=&quot;(check1 || check2) &amp;&amp; check3&quot; -- AND/OR - Make sure to use brackets

It&#39;s best practice not to do calculations directly within ngIfs, so assign the variables within your component, and do any logic there.

    boolean check1 = Your conditional check here...
    ...

For people looking to do if statements with multiple &#39;or&#39; values.

    &lt;div ng-if=&quot;::(a || b || c || d || e || f)&quot;&gt;&lt;div&gt;


Yes, it&#39;s possible.
for example checkout:

    &lt;div class=&quot;singleMatch&quot; ng-if=&quot;match.date | date:&#39;ddMMyyyy&#39; === main.date &amp;&amp;  match.team1.code === main.team1code &amp;&amp; match.team2.code === main.team2code&quot;&gt;
        //Do something here
        &lt;/div&gt;



One frequently finds expressions of this type in python questions on SO. Either for just accessing all items of the iterable

    for i in range(len(a)):
        print(a[i])

Which is just a clumbersome way of writing:

    for e in a:
        print(e)

Or for assigning to elements of the iterable:

    for i in range(len(a)):
        a[i] = a[i] * 2

Which should be the same as:

    for i, e in enumerate(a):
         a[i] = e * 2
    # Or if it isn&#39;t too expensive to create a new iterable
    a = [e * 2 for e in a]

Or for filtering over the indices:

    for i in range(len(a)):
        if i % 2 == 1: continue
        print(a[i])

Which could be expressed like this:

    for e in a [::2]:
        print(e)

Or when you just need the length of the list, and not its content:

    for _ in range(len(a)):
        doSomethingUnrelatedToA()

Which could be:

    for _ in a:
        doSomethingUnrelatedToA()

**In python we have `enumerate`, slicing, `filter`, `sorted`, etc... As python `for` constructs are intended to iterate over iterables and not only ranges of integers, are there real-world use-cases where you need `in range(len(a))`?**

Is there a need for range(len(a))?

    $ supervisorctl reread
    error: &lt;class &#39;socket.error&#39;&gt;, [Errno 111] Connection refused: file: /usr/lib64/python2.6/socket.py line: 567

I&#39;m trying to configure supervisor on my production system, but am hitting this error. The supervisor log file is empty.

When I just type `supervisorctl`, it complains:

    http://localhost:9001 refused connection

Nothing is currently listening on port 9001, AFACT: `lsof | grep TCP` returns nothing.

Supervisor socket error issue

I am trying to get started on angular development. And after reviewing the documentation some questions persist. How do i best write a `ng-if` with multiple arguments corresponding to 

`if( a &amp;&amp; b)` or `if( a || b )` 

Angular ng-if=&quot;&quot; with multiple arguments

<p>I am trying to get started on angular development. And after reviewing the documentation some questions persist. How do i best write a <code>ng-if</code> with multiple arguments corresponding to</p>
<p><code>if( a &#x26;&#x26; b)</code> or <code>if( a || b )</code></p>


I&#39;ve been trying to get a scroll to div id jquery code to work correctly. Based on another stack overflow question i tried the following

DEMO http://jsfiddle.net/kevinPHPkevin/8tLdq/

    $(&#39;#myButton&#39;).click(function() {
       $.scrollTo($(&#39;#myDiv&#39;), 1000);
    });

But it didn&#39;t work. It just snaps to the div. I also tried

    $(&#39;#myButton&#39;).click(function(event) {
         event.preventDefault();
       $.scrollTo($(&#39;#myDiv&#39;), 1000);
    });

With no progress.

Smooth scroll to div id jQuery

How can I get React to re-render the view when the browser window is resized?

### Background ###

I have some blocks that I want to layout individually on the page, however I also want them to update when the browser window changes. The very end result will be something like [Ben Holland&#39;s](http://benholland.me/javascript/how-to-build-a-site-that-works-like-pinterest/) Pinterest layout, but written using React not just jQuery. I’m still a way off.

### Code ###

Here’s my app:

    var MyApp = React.createClass({
      //does the http get from the server
      loadBlocksFromServer: function() {
        $.ajax({
          url: this.props.url,
          dataType: &#39;json&#39;,
          mimeType: &#39;textPlain&#39;,
          success: function(data) {
            this.setState({data: data.events});
          }.bind(this)
        });
      },
      getInitialState: function() {
        return {data: []};
      },
      componentWillMount: function() {
        this.loadBlocksFromServer();
    
      },	
      render: function() {
        return (
        	&lt;div&gt;
          &lt;Blocks data={this.state.data}/&gt;
          &lt;/div&gt;
        );
      }
    });

    React.renderComponent(
      &lt;MyApp url=&quot;url_here&quot;/&gt;,
      document.getElementById(&#39;view&#39;)
    )

Then I have the `Block` component (equivalent to a `Pin` in the above Pinterest example):

    var Block = React.createClass({
      render: function() {
        return (
        	&lt;div class=&quot;dp-block&quot; style={{left: this.props.top, top: this.props.left}}&gt;
        	&lt;h2&gt;{this.props.title}&lt;/h2&gt;
        	&lt;p&gt;{this.props.children}&lt;/p&gt;
        	&lt;/div&gt;
        );
      }
    });

and the list/collection of `Blocks`:

    var Blocks = React.createClass({
    
      render: function() {
        
        //I&#39;ve temporarily got code that assigns a random position
        //See inside the function below...
    
        var blockNodes = this.props.data.map(function (block) {   
          //temporary random position
          var topOffset = Math.random() * $(window).width() + &#39;px&#39;; 
          var leftOffset = Math.random() * $(window).height() + &#39;px&#39;; 
          return &lt;Block order={block.id} title={block.summary} left={leftOffset} top={topOffset}&gt;{block.description}&lt;/Block&gt;;
        });
    
        return (
        	&lt;div&gt;{blockNodes}&lt;/div&gt;
        );
      }
    });

###Question###

Should I add jQuery’s window resize? If so, where?

    $( window ).resize(function() {
      // re-render the component
    });

Is there a more “React” way of doing this?

Rerender view on browser resize with React

I have a form for replying to messages that I want to show only when `isReplyFormOpen` is true, and everytime I click the reply button I want to toggle whether the form is shown or not. How can I do this?

How do I toggle an ng-show in AngularJS based on a boolean?

The ``map`` function in underscore.js, if called with a javascript object, returns an array of values mapped from the object&#39;s values.

    _.map({one: 1, two: 2, three: 3}, function(num, key){ return num * 3; });
    =&gt; [3, 6, 9]

is there a way to make it preserve the keys? ie, I want a function that returns

    {one: 3, two: 6, three: 9}

Map over object preserving keys

What is the difference between `innerHTML`, `innerText` and `value` in JavaScript?

Difference between innerText, innerHTML and value?

This is probably simple but I can&#39;t find anything in the docs and googling didn&#39;t help. I&#39;m trying to define a state in `$stateProvider` where the URL I need to hit on the server to pull the needed data depends on a state URL parameter. In short, something like:
 

     .state(&#39;recipes.category&#39;, {
        url: &#39;/:cat&#39;,
        templateUrl: &#39;/partials/recipes.category.html&#39;,
        controller: &#39;RecipesCategoryCtrl&#39;,
        resolve: {
          category: function($http) {
            return $http.get(&#39;/recipes/&#39; + cat)
              .then(function(data) { return data.data; });
          }
        }
      })

The above doesn&#39;t work. I tried injecting `$routeParams` to get the needed `cat` parameter, with no luck. What&#39;s the right way of doing this? 


ui-router resolve with dynamic parameters

I am considering to use either Knockout or Angular or  Backbone for my personal project. I need to build some bigger, longer-running client-side interactions to go with my server-side stuff. 

I want a simple and effective way to manage data-driven user interfaces.

Which framework would you choose to solve my problem described above based on the feasibility as well as the performance aspect?

Angular.js vs Knockout.js vs Backbone.js

I am new to angularjs. I am wondering what is the way to allow only a valid number typed into a textbox.
For example, user can type in &quot;1.25&quot;, but cannot type in &quot;1.a&quot; or &quot;1..&quot;.  When user try to type in the next character which will make it an invalid number, he cannot type it in.

Thanks in advance.

How to allow only a number (digits and decimal point) to be typed in an input?

How can call a method defined in child scope from its parent scope?


    function ParentCntl() {
        // I want to call the $scope.get here
    }

    function ChildCntl($scope) {
        $scope.get = function() {
            return &quot;LOL&quot;;    
        }
    }


http://jsfiddle.net/wUPdW/

angularJS: How to call child scope function in parent scope

Why doesn&#39;t this work.

`&lt;li ng-if=&quot;!area&quot;&gt;&lt;/li&gt;`

Feels a bit illogical since

`&lt;li ng-if=&quot;area&quot;&gt;&lt;/li&gt;`

works just fine.

&#39;area&#39; is defined in scope as true/false
Any workarounds for this? I would prefer not to use ng-show/ng-hide since both of them renders items in DOM.

Angular ng-if not true

I&#39;m having a problem with trying to use Angular&#39;s `*ngFor` and `*ngIf` on the same element. 

When trying to loop through the collection in the `*ngFor`, the collection is seen as `null` and consequently fails when trying to access its properties in the template.

&lt;!-- language: lang-ts --&gt;

    @Component({
      selector: &#39;shell&#39;,
      template: `
        &lt;h3&gt;Shell&lt;/h3&gt;&lt;button (click)=&quot;toggle()&quot;&gt;Toggle!&lt;/button&gt;
        
        &lt;div *ngIf=&quot;show&quot; *ngFor=&quot;let thing of stuff&quot;&gt;
          {{log(thing)}}
          &lt;span&gt;{{thing.name}}&lt;/span&gt;
        &lt;/div&gt;
      `
    })

    export class ShellComponent implements OnInit {
      
      public stuff:any[] = [];
      public show:boolean = false;
    
      constructor() {}
    
      ngOnInit() {
        this.stuff = [
          { name: &#39;abc&#39;, id: 1 },
          { name: &#39;huo&#39;, id: 2 },
          { name: &#39;bar&#39;, id: 3 },
          { name: &#39;foo&#39;, id: 4 },
          { name: &#39;thing&#39;, id: 5 },
          { name: &#39;other&#39;, id: 6 },
        ]
      }
      
      toggle() {
        this.show = !this.show;
      }
      
      log(thing) {
        console.log(thing);
      }
    
    }

I know the easy solution is to move the `*ngIf` up a level but for scenarios like looping over list items in a `ul`, I&#39;d end up with either an empty `li` if the collection is empty, or my `li`s wrapped in redundant container elements.

Example at this [plnkr][1].

Note the console error:

    EXCEPTION: TypeError: Cannot read property &#39;name&#39; of null in [{{thing.name}} in ShellComponent@5:12]

Am I doing something wrong or is this a bug?

  [1]: http://plnkr.co/edit/C5tZ8mD3iWczVvWkWycH?p=preview

*ngIf and *ngFor on same element causing error

I&#39;m confused a bit. I need to hide block if result have one of several cases. But seems it not working correctly...

    &lt;div *ngIf=&quot;currentStatus !== &#39;open&#39; || currentStatus !== &#39;reopen&#39; &quot;&gt;
    
        &lt;p padding text-center class=&quot;text-notification&quot;&gt;{{message}}&lt;/p&gt;
    
    &lt;/div&gt;

It&#39;s just appeared with other condition. It doesn&#39;t work neither 1 condition nor for 2. Also tried `*ngIf=&quot;currentStatus !== (&#39;open&#39; ||  &#39;reopen&#39;) &quot;` but it&#39;s works ok only for 1 case. 

angular 4: *ngIf with multiple conditions

How would I have multiple cases in an `*ngIf` statement? I&#39;m used to Vue or Angular 1 with having an `if`, `else if`, and `else`, but it seems like Angular 4 only has a `true` (`if`) and `false` (`else`) condition.

According to the documentation, I can only do:

    &lt;ng-container *ngIf=&quot;foo === 1; then first else second&quot;&gt;&lt;/ng-container&gt;
    &lt;ng-template #first&gt;First&lt;/ng-template&gt;
    &lt;ng-template #second&gt;Second&lt;/ng-template&gt;
    &lt;ng-template #third&gt;Third&lt;/ng-template&gt;

But I want to have multiple conditions (something like):

    &lt;ng-container *ngIf=&quot;foo === 1; then first; foo === 2; then second else third&quot;&gt;&lt;/ng-container&gt;
    &lt;ng-template #first&gt;First&lt;/ng-template&gt;
    &lt;ng-template #second&gt;Second&lt;/ng-template&gt;
    &lt;ng-template #third&gt;Third&lt;/ng-template&gt;

But I&#39;m ending up having to use `ngSwitch`, which feels like a hack:

    &lt;ng-container [ngSwitch]=&quot;true&quot;&gt;
      &lt;div *ngSwitchCase=&quot;foo === 1&quot;&gt;First&lt;/div&gt;
      &lt;div *ngSwitchCase=&quot;bar === 2&quot;&gt;Second&lt;/div&gt;
      &lt;div *ngSwitchDefault&gt;Third&lt;/div&gt;
    &lt;/ng-container&gt;

Alternately, it seems like a lot of the syntaxes I&#39;ve got used to from Angular 1 and Vue aren&#39;t supported in Angular 4, so what would be the recommended way to structure my code with conditions like this?




Content Type	Original Author	Original Content on Stackoverflow
Question	David Karlsson	View Question on Stackoverflow
Solution 1 - Javascript	javaCity	View Answer on Stackoverflow
Solution 2 - Javascript	Chris	View Answer on Stackoverflow
Solution 3 - Javascript	Brendan Metcalfe	View Answer on Stackoverflow
Solution 4 - Javascript	Vithal Reddy	View Answer on Stackoverflow

Angular ng-if="" with multiple arguments

Javascript Problem Overview

Javascript Solutions

Solution 1 - Javascript

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Solution 4 - Javascript

Supervisor socket error issue

Is there a need for range(len(a))?

Attributions