Testing them out in a real simple case yields the same output:

    const obj = {a: 5, b: 5};
    console.log(Reflect.ownKeys(obj));
    console.log(Object.keys(obj));

    // Result
    [&#39;a&#39;, &#39;b&#39;]
    [&#39;a&#39;, &#39;b&#39;]

When does `Reflect.ownKeys(obj)` produce output different from `Object.keys(obj)`?

What is the difference between Reflect.ownKeys(obj) and Object.keys(obj)?

What is wrong with the below code

    -(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath{
        
        NSString *CellIdentifier  = @&quot;Cell&quot;;
    
        UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier]; 
        
        cell.textLabel.text = @&quot;hello&quot;;
        
        return cell;
    }
And   

    -(NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section{
        return 2;
    }
but I&#39;m getting **failed to obtain a cell from its dataSource**

The entire exception is 

    *** Terminating app due to uncaught exception &#39;NSInternalInconsistencyException&#39;, reason: &#39;UITableView (&lt;UITableView: 0x7ffe0b092800; frame = (0 97; 414 590); clipsToBounds = YES; autoresize = RM+BM; gestureRecognizers = &lt;NSArray: 0x7ffe0acf3b10&gt;; layer = &lt;CALayer: 0x7ffe0aceb6e0&gt;; contentOffset: {0, 0}; contentSize: {414, 88}&gt;) failed to obtain a cell from its dataSource (&lt;AllContactsViewController: 0x7ffe0ace60f0&gt;)&#39;


I have set delegate and data source for the table view

Failed to obtain a cell from its DataSource

Hello Friends all I&#39;m trying to do is change the background color of a checkbox. I tired many things but nothing works. Can some one help?

        input[type=&quot;checkbox&quot;] {
	      background: #3d404e;
	      border: #7f83a2 1px solid;
       }

How to change the background color on a input checkbox with css?

Hello Friends all I'm trying to do is change the background color of a checkbox. I tired many things but nothing works. Can some one help?
<pre><code class="hljs language-css"> input[type="checkbox"] {
 background: #3d404e;
 border: #7f83a2 1px solid;
 }
</code></pre>

Recently I&#39;ve started using the calc(...) method within CSS.  I quickly learned that code such as: `width: calc(100%-2)` will not work, though adding white-space before and after the `-` operator will fix the problem and the calc method will function properly.

After doing a bit of research I found multiple blog posts reference that the white-space is required and many have even pointed to the specification ([CSS3 8.1.1][1]) which states:

&gt; In addition, whitespace is required on both sides of the + and -
&gt; operators. (The * and / operaters can be used without whitespace
&gt; around them.)

Now, clearly, the spec tells us that these operators must be wrapped in white-space, but why?  I&#39;ve read further within the spec (through sections 8.1.2-4) and if it&#39;s explained in these additional portions, I&#39;m not understanding the reasoning.

In simple terms, could someone explain why it was specified that `calc(100% - 1)` or even `calc(100%/2)` is acceptable syntax but not `calc(100%-1)`?

  [1]: http://www.w3.org/TR/css3-values/#calc-syntax

Why must a + or - be surrounded with whitespace from within the Calc() method?

This is, in effect, the Pinterest layout. However, the solutions found online are wrapped in columns, which means the container inadvertently grows horizontally. That is **not** the Pinterest layout, and it does not work well with dynamically-loaded content.

What I want to do is have a bunch of images of fixed width and asymmetrical height, laid out horizontally but wrapping in a new row when the limits of the fixed-width container are met:

[![][1]][1]

Can flexbox do this, or do I have to resort to a JS solution like Masonry?

  [1]: http://i.stack.imgur.com/yZAVW.jpg

Is it possible for flex items to align tightly to the items above them?

I have a spinning gear on my website displayed with this code:

    

&lt;!-- begin snippet: js hide: false --&gt;

&lt;!-- language: lang-html --&gt;

    &lt;link rel=&quot;stylesheet&quot;
     href=&quot;https://maxcdn.bootstrapcdn.com/font-awesome/4.5.0/css/font-awesome.min.css&quot;/&gt;

    &lt;i class = &quot;fa fa-cog fa-5x fa-spin&quot;&gt;&lt;/i&gt;

&lt;!-- end snippet --&gt;

Personally, I think that the speed of the gear is too fast. Can I modify it with CSS?

Can we modify a Font Awesome spin speed?

I am contributing to an Open Source Project where I am developing Material design for React Native. I am blocked at work,I am unable to make some UI level enhancements w.r.t. padding, alignment etc.,

This is the Official Spec of Material Design for Drawer-

[![According to the spec of Material Design][1]][1]

In the above image, the **UNIT** of measurement is **dp**.

But, in my React Native code, I see there is no such units mentioned. Considering it is &quot;react native&quot; I am confused whether it is **px** or **dp**.

I even went over the Official Docs of [React Native for Style][2] component. I don&#39;t see a mention anywhere.

My Code looks like-

    const styles = {
        touchable: {
            paddingHorizontal: 16,
            marginVertical: 8,
            height: 48
        },
        item: {
            flex: 1,
            flexDirection: &#39;row&#39;,
            alignItems: &#39;center&#39;,
        },
        icon: {
            position: &#39;relative&#39;,
        },
        value: {
            flex: 1,
            paddingLeft: 34,
            top: 2
        },
        label: {
            top: 2
        }
    },

Please can you tell me, if this is pixels or dp? And also, is ```1px = 1dp```?

  [1]: http://i.stack.imgur.com/057YP.png
  [2]: https://facebook.github.io/react-native/docs/style.html

What is the default unit of style in React Native?

I am new to ReactJS and JSX and I am having a little problem with the code below. 

I am trying to add multiple classes to the `className` attribute on each `li`:

    


&lt;!-- language: lang-html --&gt;

    &lt;li key={index} className={activeClass, data.class, &quot;main-class&quot;}&gt;&lt;/li&gt;


My React component is:

    


&lt;!-- language: lang-jsx --&gt;

    var AccountMainMenu = React.createClass({
      getInitialState: function() {
        return { focused: 0 };
      },

      clicked: function(index) {
        this.setState({ focused: index });
      },

      render: function() {
        var self = this;
        var accountMenuData = [
          {
            name: &quot;My Account&quot;,
            icon: &quot;icon-account&quot;
          },
          {
            name: &quot;Messages&quot;,
            icon: &quot;icon-message&quot;
          },
          {
            name: &quot;Settings&quot;,
            icon: &quot;icon-settings&quot;
          }
        /*{
            name:&quot;Help &amp;amp; Support &amp;nbsp; &lt;span class=&#39;font-awesome icon-support&#39;&gt;&lt;/span&gt;(888) 664.6261&quot;,
            listClass:&quot;no-mobile last help-support last&quot;
          }*/
        ];

        return (
          &lt;div className=&quot;acc-header-wrapper clearfix&quot;&gt;
            &lt;ul className=&quot;acc-btns-container&quot;&gt;
              {accountMenuData.map(function(data, index) {
                var activeClass = &quot;&quot;;

                if (self.state.focused == index) {
                  activeClass = &quot;active&quot;;
                }

                return (
                  &lt;li
                    key={index}
                    className={activeClass}
                    onClick={self.clicked.bind(self, index)}
                  &gt;
                    &lt;a href=&quot;#&quot; className={data.icon}&gt;
                      {data.name}
                    &lt;/a&gt;
                  &lt;/li&gt;
                );
              })}
            &lt;/ul&gt;
          &lt;/div&gt;
        );
      }
    });

    ReactDOM.render(&lt;AccountMainMenu /&gt;, document.getElementById(&quot;app-container&quot;));





How to add multiple classes to a ReactJS Component?

I&#39;m trying to get an SVG Favicon on my site but no matter what I do, it just doesn&#39;t want to work.

I&#39;ve got the following code saved as an .svg file in my usual favicon location, but when I change the favicon path to be .svg instead of .ico, nothing loads.

    &lt;svg version=&quot;1.1&quot; xmlns=&quot;http://www.w3.org/2000/svg&quot; xmlns:xlink=&quot;http://www.w3.org/1999/xlink&quot; x=&quot;0px&quot; y=&quot;0px&quot; viewBox=&quot;0 0 384.5 283.4&quot; style=&quot;enable-background:new 0 0 384.5 283.4;&quot; xml:space=&quot;preserve&quot;  width=&quot;100%&quot; height=&quot;100%&quot;&gt;

    &lt;style type=&quot;text/css&quot;&gt;
        .shape1 {fill: #DB6B2A;}
    	.shape2 {fill: #AE1A31;}
    &lt;/style&gt;

    &lt;path class=&quot;shape1&quot; d=&quot;M384.5,83.7c-4.6-19.3-14.3-36.3-29.3-51.3C333.4,10.6,307.6,0,276.7,0c-30.9,0-56.7,10.6-78.4,32.4
	l-4.6,5.1l-4.5-5.1C167.4,10.6,141.6,0,110.8,0S54.1,10.6,32.4,32.4C10.6,54.1,0,79.9,0,110.8v61.1l55.1-12.8v-48.4
	c0-15.2,5.6-28.3,16.2-39C82,60.7,95.1,55.1,110.8,55.1c30.4,0,55.1,25.3,55.1,55.6v22.9l55.6-12.7v-10.1c0-2.5,0-4.6-0.5-7.1
	c1.5-12.1,7.1-22.8,16.2-31.9c10.6-11.1,23.8-16.7,39.5-16.7c25.4,0,46.9,17.2,53.3,40.7&quot;/&gt;

    &lt;path class=&quot;shape2&quot; d=&quot;M54.5,187.6c6.4,23.5,27.9,40.7,53.3,40.7c15.7,0,28.8-5.6,39.5-16.7c9.1-9.1,14.7-19.7,16.2-31.9
	c-0.5-2.5-0.5-4.6-0.5-7.1v-10.1l55.6-12.7v22.9c0,30.4,24.8,55.6,55.1,55.6c15.7,0,28.8-5.6,39.5-16.7
	c10.6-10.6,16.2-23.8,16.2-38.9v-48.4l55.1-12.7v61.1c0,30.9-10.6,56.7-32.4,78.4c-21.7,21.7-47.5,32.4-78.4,32.4
	c-30.9,0-56.7-10.6-78.4-32.4l-4.6-5.1l-4.6,5.1c-21.7,21.7-47.6,32.4-78.4,32.4s-56.7-10.6-78.4-32.4C14.3,236,4.6,219,0,199.7&quot;/&gt;
    &lt;/svg&gt;

This is the code I&#39;m using to set the favicon;

    &lt;link rel=&quot;icon&quot; href=&quot;http://www.MYSITE.co.uk/favicon.svg?v=4&quot;&gt;

I can&#39;t work out if it is an issue with my .svg code, or I&#39;m missing something.
Thanks

SVG Favicon Not Working

As you can see in the demo below, `margin: auto;` centers the blue `div` horizontally, but not vertically. Why not?

&lt;!-- begin snippet: js hide: false --&gt;

&lt;!-- language: lang-css --&gt;

    .box {
      border: 1px solid red;
      width: 100px;
      height: 100px;
    }
    .center {
      background: blue;
      width: 50px;
      height: 50px;
      margin: auto;
    }

&lt;!-- language: lang-html --&gt;

    &lt;div class=&quot;box&quot;&gt;
      &lt;div class=&quot;center&quot;&gt;&lt;/div&gt;
    &lt;/div&gt;


&lt;!-- end snippet --&gt;

My question is not asking for workarounds.

Why doesn&#39;t &quot;margin: auto&quot; center an element vertically?

Since the latest update to Visual Studio 2015, I get this message when I open `.html` or `.cshtml` files. Clicking &quot;Don&#39;t Ask Again&quot; only disables this until VS is restarted. How can I turn it off permanently?

[![enter image description here][1]][1]


  [1]: http://i.stack.imgur.com/j0jIj.png

Visual Studio 2015- How to disable &quot;based on your project, we have identified extensions you may find helpful&quot; message?

When working with flex align-* properties, what&#39;s the difference between `flex-start` and `baseline`?

The below code snippet gives same output for `align-self: flex-start` and `align-self: baseline`.

In which cases will `align-self: flex-start` and `align-self: baseline` behave differently?

&lt;!-- begin snippet: js hide: true console: false babel: false --&gt;

&lt;!-- language: lang-css --&gt;

    .flex-container {
      color: white;
      display: -webkit-flex;
      display: flex;
      width: 350px;
      height: 200px;
      background-color: yellow;
    }
    .flex-item {
      background-color: green;
      width: 50px;
      min-height: 100px;
      margin: 10px;
    }
    .item1 {
      -webkit-align-self: flex-start;
      align-self: flex-start;
    }
    .item2 {
      -webkit-align-self: flex-end;
      align-self: flex-end;
    }
    .item3 {
      -webkit-align-self: center;
      align-self: center;
    }
    .item4 {
      -webkit-align-self: baseline;
      align-self: baseline;
    }
    .item5 {
      -webkit-align-self: stretch;
      align-self: stretch;
    }

&lt;!-- language: lang-html --&gt;

    &lt;div class=&quot;flex-container&quot;&gt;
      &lt;div class=&quot;flex-item item1&quot;&gt;flex-start&lt;/div&gt;
      &lt;div class=&quot;flex-item item4&quot;&gt;baseline&lt;/div&gt;
      &lt;div class=&quot;flex-item item2&quot;&gt;flex-end&lt;/div&gt;
      &lt;div class=&quot;flex-item item3&quot;&gt;center&lt;/div&gt;
      &lt;div class=&quot;flex-item item5&quot;&gt;stretch&lt;/div&gt;
    &lt;/div&gt;

&lt;!-- end snippet --&gt;



What&#39;s the difference between flex-start and baseline?

My problem is really simple: I have a list of checkboxes like this:

    &lt;div class=&quot;form-group&quot;&gt;
        &lt;label for=&quot;options&quot;&gt;Options :&lt;/label&gt;
        &lt;label *ngFor=&quot;#option of options&quot; class=&quot;form-control&quot;&gt;
            &lt;input type=&quot;checkbox&quot; name=&quot;options&quot; value=&quot;option&quot; /&gt; {{option}}
        &lt;/label&gt;
    &lt;/div&gt;

And I would like to send an array of the selected options, something like:
`[option1, option5, option8]` if options 1, 5 and 8 are selected. This array is part of a JSON that I would like to send via an HTTP PUT request.


Thanks for your help!

Angular 2: Get Values of Multiple Checked Checkboxes

I am having a very annoying issue with React and checkboxes. The application I am working with requires a list of checkboxes that represent settings that are persisted in the back-end. **There is an option to restore the settings to their original state**.

At first, I created a component that has an object like a map of settings. Each setting has a key and a boolean value. Hence:

    {
        bubbles: true,
        gregory: false
    }

Is to be represented as:

    &lt;input type=&quot;checkbox&quot; value=&quot;bubbles&quot; checked=&quot;checked&quot; /&gt;
    &lt;input type=&quot;checkbox&quot; value=&quot;gregory&quot; /&gt;

Now, it seems React is ignorant about how a checkbox is supposed to work. I don&#39;t want to set the checkboxes&#39; values, I want the &quot;checked&quot; property.

Yet, if I try something like this:

    &lt;input
        type=&quot;checkbox&quot;
        value={setting}
        checked={this.settings[setting]}
        onChange={this.onChangeAction.bind(this)}
    /&gt;

I get this warning:

&gt; Warning: AwesomeComponent is changing an uncontrolled input of type checkbox to be controlled. Input elements should not switch from uncontrolled to controlled (or vice versa). Decide between using a controlled or uncontrolled input element for the lifetime of the component. More info: [_some useless docs page I read several times to no avail_]

So I decided to create another component to wrap each individual checkbox and I got this:

    &lt;input
        type=&quot;checkbox&quot;
        checked={this.state.checked}
        onChange={this.onChangeAction.bind(this)}
    /&gt;

Now the `checked` is a property present directly in my state.

This yields the same warning, so I tried using `defaultChecked`:

    &lt;input
        type=&quot;checkbox&quot;
        defaultChecked={this.state.checked}
        onChange={this.onChangeAction.bind(this)}
    /&gt;

Which makes the warning disappear, but now it is unable to reset the `checked` value to the default one. So I tried playing with the method `componentWillReceiveProps`, this way I am quite sure my state is correct, `this.state.checked` is correct and the component renders again.

And it does. But the checkbox remains as it was originally.
For now I left that ugly warning and I am using `checked`.
How do I fix this thing so the warning goes away?

I was thinking that perhaps there is a way to force-re-render the component, so it captures the new `defaultChecked` value and uses it. But I don&#39;t know how to do that. Perhaps suppress the warning **only** for this component? Is that possible? Perhaps there is something else that can be done?

Setting a checkbox &quot;check&quot; property in React

I&#180;m fairly new to Angular2 and I have a little problem:

In my Login-Component-HTML, I have two checkboxes, which I want to bind in two way data-binding to the Login-Component-TypeScript.

**This is the HTML:**

    &lt;div class=&quot;checkbox&quot;&gt;
    &lt;label&gt;
        &lt;input #saveUsername [(ngModel)]=&quot;saveUsername.selected&quot; type=&quot;checkbox&quot; data-toggle=&quot;toggle&quot;&gt;Save username
    &lt;/label&gt;
    &lt;/div&gt;

**And this is the Component.ts:**

    import { Component, OnInit }    from &#39;@angular/core&#39;;
    import { Router }               from &#39;@angular/router&#39;;
    import { Variables }            from &#39;../../services/variables&#39;;
    
    @Component({
        selector: &#39;login&#39;,
        moduleId: module.id,
        templateUrl: &#39;login.component.html&#39;,
        styleUrls: [&#39;login.component.css&#39;]
    })
    
    
    export class LoginComponent implements OnInit {
    
        private saveUsername: boolean = true;
        private autoLogin: boolean = true;
        constructor(private router: Router, private variables: Variables) { }
    
        ngOnInit() { 
            this.loginValid = false;
            // Get user name from local storage if you want to save

            if (window.localStorage.getItem(&quot;username&quot;) === null) {
               this.saveUsername = true;
               this.autoLogin = true;
               console.log(this.saveUsername, this.autoLogin);
            } else {
               console.log(&quot;init&quot;, window.localStorage.getItem(&quot;username&quot;));
            }
        }
    
        login(username: string, password: string, saveUsername: boolean, autoLogin: boolean) {
            this.variables.setUsername(username);
            this.variables.setPassword(password);
            this.variables.setIsLoggedIn(true);
            console.log(saveUsername, autoLogin);
            //this.router.navigate([&#39;dashboard&#39;]);
        }

If I click an checkbox, I get the correct value in the controller (component).

But if I change the value of for example `saveUsername` in the component, the checkbox didn&#39;t &quot;get&quot; the new value.

So I can&#180;t manipulate the checkbox from the Component (like I want to do in the `ngOnInit` in the component.

Thanks for your help!

Angular 2 Checkbox Two Way Data Binding

I&#39;m using JS as a way of changing the content of an SPA I&#39;m creating. When I press a button to change the content the HTML changes from this:

    

&lt;!-- language: lang-html --&gt;

    &lt;div id=&quot;selectDiv&quot; style=&quot;display: none;&quot;&gt;



to this:

&lt;!-- language: lang-html --&gt;

    &lt;div id=&quot;selectDiv&quot; style&gt;

Now part of my SPA has a div that contains a number of checkboxes, each representing a div, and so when I press the submit button, the next div that should be displayed will be the first item in the checkbox list that was selected.

I&#39;m wondering if there&#39;s a way in JQuery for the code to &quot;almost detect&quot; which div is now visible. something like this:

    if($(&#39;#selectDiv&#39;).isVisible()){
        //JS code associated with this div.
    }

Any suggestions?

JQuery: if div is visible

Given a list of checkboxes bound to the same `formControlName`, how can I produce an array of checkbox values bound to the `formControl`, rather than simply `true`/`false`?

**Example:**

    &lt;form [formGroup]=&quot;checkboxGroup&quot;&gt;
        &lt;input type=&quot;checkbox&quot; id=&quot;checkbox-1&quot; value=&quot;value-1&quot; formControlName=&quot;myValues&quot; /&gt;
        &lt;input type=&quot;checkbox&quot; id=&quot;checkbox-2&quot; value=&quot;value-2&quot; formControlName=&quot;myValues&quot; /&gt;
        &lt;input type=&quot;checkbox&quot; id=&quot;checkbox-3&quot; value=&quot;value-2&quot; formControlName=&quot;myValues&quot; /&gt;
    &lt;/form&gt;

**`checkboxGroup.controls[&#39;myValues&#39;].value` currently produces:**

    true or false

**What I want it to produce:**

    [&#39;value-1&#39;, &#39;value-2&#39;, ...]

    

Angular ReactiveForms: Producing an array of checkbox values?

I have seen this question a lot both on SO and the Web. But none of them has been what I am looking for.

How do I add a color-overlay to a background image using CSS only?

Example HTML:

    &lt;div class=&quot;testclass&quot;&gt;
    &lt;/div&gt;

Example CSS:

    .testclass {
        background-image: url(&quot;../img/img.jpg&quot;);
    }

Please note:

 - I want to solve this by only using CSS. i.e I do NOT want to add a child div within the div &quot;testclass&quot; for the color overlay.

 - This should not be a &quot;hover effect&quot; I want to simply just add a color-overay to the background image.

 - I want to be able to use opacity i.e. I am looking for a solution that allows RGBA color.

 - I am looking for just one color, lets say black. Not a gradient.


Is this possible? (I would be surprised if not, but I have not been able to find anything about this), and if so what the best way to accomplish this? 

All suggestions and advice are appreciated!

  

How to add a color overlay to a background image?

Visual Studio Code&#39;s default status bar color is blue, and I find it quite distracting. I used [this extension][1] to change the color, but it has stopped working after the *1.10.2* update.

  [1]: https://marketplace.visualstudio.com/items?itemName=bentx.vscode-custom-theme

Visual Studio Code status bar color

I have a Flutter Container widget and I defined a color for it (pink), but for some reason, the color in BoxDecoration overrides it (green). Why?

    new Container(
      color: Colors.pink,
      decoration: new BoxDecoration(
        borderRadius: new BorderRadius.circular(16.0),
        color: Colors.green,
      ),
    );

Flutter BoxDecoration’s background color overrides the Container&#39;s background color, why?

I&#39;ve made a `ListView` in Flutter, but now I have some `ListTiles` in this `ListView` that can be selected. Upon selection, I want the background color to change to a color of my choice. I don&#39;t know how to do that.
In [the docs][1] they mention that a `ListTile` has a property `style`. However, when I try to add that (as in third last line in the code below), this `style` property gets a squiggly red line underneath and the compiler tells me that `The named parameter &#39;style&#39; isn&#39;t defined`.


    Widget _buildRow(String string){
      return new ListTile(
        title: new Text(string),
        onTap: () =&gt; setState(() =&gt; toggleSelection(string)),
        selected: selectedFriends.contains(string),
        style: new ListTileTheme(selectedColor: Colors.white,),
      );
    }


  [1]: https://docs.flutter.io/flutter/material/ListTileTheme/style.html

Change background color of ListTile upon selection in Flutter

Why does the final color of two stacked semi-translucent boxes depend on the order?

How could I make it so that I get the same color in both cases?

&lt;!-- begin snippet: js hide: false console: true babel: false --&gt;

&lt;!-- language: lang-css --&gt;

    .a {
      background-color: rgba(255, 0, 0, 0.5)
    }

    .b {
      background-color: rgba(0, 0, 255, 0.5)
    }

&lt;!-- language: lang-html --&gt;

    &lt;span class=&quot;a&quot;&gt;&lt;span class=&quot;b&quot;&gt;          Color 1&lt;/span&gt;&lt;/span&gt;
    &lt;span class=&quot;b&quot;&gt;&lt;span class=&quot;a&quot;&gt;Different Color 2&lt;/span&gt;&lt;/span&gt;

&lt;!-- end snippet --&gt;



How to change the background color on a input checkbox with css?

Css Problem Overview

Css Solutions

Failed to obtain a cell from its DataSource

What is the difference between Reflect.ownKeys(obj) and Object.keys(obj)?

Attributions