Well, as the error says, `innerHTML` is not a function.

You can **assign a value to the property**, though:

    document.getElementById(&quot;dated&quot;).innerHTML = month + &quot;/&quot; + day + &quot;/&quot; + year;

For more infos, **have a look at [the MDN docs](https://developer.mozilla.org/en-US/docs/Web/API/Element/innerHTML)**.


innerHTML is a property... thus you need to use = not ()... it&#39;s not jQuery.

    document.getElementById(&quot;dated&quot;).innerHTML = &quot;blah&quot;

    document.getElementById(&quot;dated&quot;).innerHTML = month + &quot;/&quot; + day + &quot;/&quot; + year;

I want to create a string with embedded information.  One way (not the only way) of achieving what I want is called [string interpolation][1] or variable substitution, wherein placeholders in a string are replaced with actual values.

In C, I would do something like this:

&lt;!-- language: lang-c --&gt;

    printf(&quot;error! value was %d but I expected %d&quot;,actualValue,expectedValue)

whereas if I were programming in python, I would do something like this:

&lt;!-- language: lang-python --&gt;

    &quot;error! value was {0} but I expected {1}&quot;.format(actualValue,expectedValue)

both of these are examples of string interpolation.

How can I do this in C++?

**Important Caveats**:

1. I know that I can use ``std::cout`` if I want to print such a message to standard output (not string interpolation, but prints out the kind of string I want):

&lt;!-- language: lang-c++ --&gt;

    cout &lt;&lt; &quot;error! value was &quot; &lt;&lt; actualValue &lt;&lt; &quot; but I expected &quot;
    &lt;&lt; expectedValue;

I don&#39;t want to *print* a string to stdout.  I want to pass a `std::string` as an argument to a function (e.g. the constructor of an exception object).

2. I am using C++11, but portability is potentially an issue, so knowing which methods work and don&#39;t work in which versions of C++ would be a plus.

**Edit**

3. For my immediate usage, I&#39;m not concerned about performance (I&#39;m raising an exception for cryin&#39; out loud!).  *However*, knowing the relative performance of the various methods would be very very useful in general.

4. Why not just use printf itself (C++ is a superset of C after all...)?  [This answer][2] discusses some reasons why not.  As far as I can understand, type safety is a big reason: if you put %d, the variable you put in there had better really be convertible to an integer, as that&#39;s how the function figures out what type it is.  It would be much safer to have a method which uses compile-time knowledge of the actual type of the variables to be inserted.


  [1]: https://en.wikipedia.org/wiki/String_interpolation
  [2]: https://stackoverflow.com/a/2872576/407588

How to construct a std::string with embedded values, i.e. &quot;string interpolation&quot;?

I&#39;m building my first iOS application, and I am using Firebase to handle authentication, database, etc. I added a sign up screen and used the following code to create a new user: 

    FIRAuth.auth()?.createUserWithEmail(emailAddress.text!, password: password.text!, completion: { (user, error) in
                
            })

When the user taps on the sign up button, there is a segue that should take them back to the original login view controller. However, when I got to run the app, it hangs on the launch screen. Here is the debugger output:

    2016-06-19 14:35:05.402 unitaskr[4386:82981] Configuring the default app.
    2016-06-19 14:35:05.413 unitaskr[4386:] &lt;FIRAnalytics/INFO&gt; Firebase Analytics     v.3200000 started
    2016-06-19 14:35:05.414 unitaskr[4386:] &lt;FIRAnalytics/INFO&gt; To enable debug logging set the following application argument: -FIRAnalyticsDebugEnabled (see ...)
    2016-06-19 14:35:05.419: &lt;FIRInstanceID/WARNING&gt; FIRInstanceID AppDelegate proxy enabled, will swizzle app delegate remote notification handlers. To disable add &quot;FirebaseAppDelegateProxyEnabled&quot; to your Info.plist and set it to NO
    2016-06-19 14:35:05.418 unitaskr[4386:] &lt;FIRAnalytics/INFO&gt; Successfully created Firebase Analytics App Delegate Proxy automatically. To disable the proxy, set the flag FirebaseAppDelegateProxyEnabled to NO in the Info.plist
    2016-06-19 14:35:05.430 unitaskr[4386:82981] *** Terminating app due to uncaught exception &#39;com.firebase.core&#39;, reason: &#39;Default app has already been configured.&#39;
    *** First throw call stack:
    (
	0   CoreFoundation                      0x00000001100a8d85   __exceptionPreprocess + 165
	1   libobjc.A.dylib                     0x00000001108e7deb objc_exception_throw + 48
	2   CoreFoundation                      0x00000001100a8cbd +[NSException raise:format:] + 205
	3   unitaskr                            0x000000010b58844d +[FIRApp    configureDefaultAppWithOptions:sendingNotifications:] + 102
	4   unitaskr                            0x000000010b588238 +[FIRApp configure] + 302
	5   unitaskr                            0x000000010b541f1a _TFC8unitaskr11AppDelegate11applicationfTCSo13UIApplication29didFinishLaunchingWithOptionsGSqGVs10DictionaryCSo8NSObjectPs9AnyObject____Sb + 266
	6   unitaskr                            0x000000010b542204 _TToFC8unitaskr11AppDelegate11applicationfTCSo13UIApplication29didFinishLaunchingWithOptionsGSqGVs10DictionaryCSo8NSObjectPs9AnyObject____Sb + 180
	7   UIKit                               0x000000010e5bf9ac -[UIApplication _handleDelegateCallbacksWithOptions:isSuspended:restoreState:] + 272
	8   UIKit                               0x000000010e5c0c0d -[UIApplication _callInitializationDelegatesForMainScene:transitionContext:] + 3415
	9   UIKit                               0x000000010e5c7568 -[UIApplication _runWithMainScene:transitionContext:completion:] + 1769
	10  UIKit                               0x000000010e5c4714 -[UIApplication workspaceDidEndTransaction:] + 188
	11  FrontBoardServices                  0x00000001127b78c8 __FBSSERIALQUEUE_IS_CALLING_OUT_TO_A_BLOCK__ + 24
	12  FrontBoardServices                  0x00000001127b7741 -[FBSSerialQueue _performNext] + 178
	13  FrontBoardServices                  0x00000001127b7aca -[FBSSerialQueue _performNextFromRunLoopSource] + 45
	14  CoreFoundation                      0x000000010ffce301 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 17
	15  CoreFoundation                      0x000000010ffc422c __CFRunLoopDoSources0 + 556
	16  CoreFoundation                      0x000000010ffc36e3 __CFRunLoopRun + 867
	17  CoreFoundation                      0x000000010ffc30f8 CFRunLoopRunSpecific + 488
	18  UIKit                               0x000000010e5c3f21 -[UIApplication _run] + 402
	19  UIKit                               0x000000010e5c8f09 UIApplicationMain + 171
	20  unitaskr                            0x000000010b542a42 main + 114
	21  libdyld.dylib                       0x00000001113b692d start + 1
    )
    libc++abi.dylib: terminating with uncaught exception of type NSException
    (lldb) 


I can provide additional information as needed, any help/advice would be greatly appreciated as I am just starting out and looking to learn as much as possible. Have a great day! 

App crashing when using Firebase Auth, reason: &#39;Default app has already been configured.&#39;

I&#39;m trying to fill the date automatically in a table header, but all I get is 

&gt;&quot;.innerHTML is not a function&quot;

I&#39;ve looked everywhere, and tried put my code at the top and bottom of the page, but nothing works. Help, please!


    window.onload = function() {
      var currentTime = new Date();
      var month = currentTime.getMonth() + 1;
      var day = currentTime.getDate();
      var year = currentTime.getFullYear();
      document.getElementById(&quot;dated&quot;).innerHTML(month + &quot;/&quot; + day + &quot;/&quot; + year);
    };

Error message &quot;.innerHTML is not a function&quot;

I'm trying to fill the date automatically in a table header, but all I get is
>".innerHTML is not a function"
I've looked everywhere, and tried put my code at the top and bottom of the page, but nothing works. Help, please!
<pre><code class="hljs language-ini">window.onload = function() {
 var currentTime = new Date();
 var month = currentTime.getMonth() + 1;
 var day = currentTime.getDate();
 var year = currentTime.getFullYear();
 document.getElementById("dated").innerHTML(month + "/" + day + "/" + year);
};
</code></pre>

Here&#39;s what I have in fruit.ts

    export type Fruit = &quot;Orange&quot; | &quot;Apple&quot; | &quot;Banana&quot;

Now I&#39;m importing fruit.ts in another typescript file. Here&#39;s what I have


    myString:string = &quot;Banana&quot;;
    
    myFruit:Fruit = myString;


When I do

    myFruit = myString;

I get an error:

&gt; Type &#39;string&#39; is not assignable to type &#39;&quot;Orange&quot; | &quot;Apple&quot; |
&gt; &quot;Banana&quot;&#39;

How can I assign a string to a variable of custom type Fruit?

Typescript Type &#39;string&#39; is not assignable to type

I have a function which I have written which basically looks like this:

    function getNextCard(searchTerms) {
      // Setup Some Variables

      // Do a bunch of logic to pick the next card based on termed passed through what I&#39;ll call here as &#39;searchTerms&#39; all of this logic is omitted because it&#39;s not important for my question.
      // ...

      // If we find a next card to give, than give it
      if (nextCardFound)
        return nextCardFound;

      // Otherwise - I&#39;m returning undefined
      return undefined;
    }

**Question: Would it be better to return &quot;null&quot; here?**

I can pass whatever I want back - obviously...  I just wasn&#39;t sure what is the best thing to use.

The code that calls this function knows how to deal with undefined (it actually won&#39;t ever really happen unless something goes horribly wrong)

The reason I&#39;m asking this question is that I heard somewhere something that sounded like &quot;Don&#39;t assign undefined to variables&quot; or something - that it will make it harder to debug.  So, the fact that I can see that `null` gets passed back tells me that the return is working - but basically function similar to `undefined`.

- - -

## Documentation:

[Mozilla Docs](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/undefined) Didn&#39;t answer my question... google didn&#39;t either :\

[This SO Question](https://stackoverflow.com/questions/6604749/what-reason-is-there-to-use-null-instead-of-undefined-in-javascript) - was way too broad for what I&#39;m trying to figure out here.

Is it better to return `undefined` or `null` from a javascript function?

How to sort this map by value?

    var map = new Map();
    map.set(&#39;orange&#39;, 10);
    map.set(&#39;apple&#39;, 5);
    map.set(&#39;banana&#39;, 20);
    map.set(&#39;cherry&#39;, 13);



How to sort a map by value in JavaScript?

I have a component called OrderItem that takes an object with multiple objects (at least two) inside it, and renders them as multiple rows inside a table.  There will be multiple OrderItem components inside the table. The problem is that in the component&#39;s render function, I can&#39;t return multiple &lt;tr&gt; lines.  I can only return a single component, and if I wrap them in a div, it says &quot; `&lt;tr&gt;` cannot appear as a child of `&lt;div&gt;`&quot;

The code looks something like this (I left some stuff out for easier readability)

&lt;!-- language: lang-js --&gt;

    Parent() {
      render() {
        return (
          &lt;table&gt;
            &lt;tbody&gt;
              {
                _.map(this.state.orderItems, (value, key) =&gt; {
                  return &lt;OrderItem value={value} myKey={key}/&gt;
                })
              }
            &lt;/tbody&gt;
          &lt;/table&gt;
        )
      }
    }

    class OrderItem extends React.Component {
      render() {
        return (
          &lt;div&gt; // &lt;-- problematic div
    	    &lt;tr key={this.props.myKey}&gt;
    	      &lt;td&gt; Table {this.props.value[0].table}&lt;/td&gt;
    	      &lt;td&gt; Item &lt;/td&gt;
    	      &lt;td&gt; Option &lt;/td&gt;
    	    &lt;/tr&gt;
    	    {this.props.value.map((item, index) =&gt; {
    	      if (index &gt; 0) { // skip the first element since it&#39;s already used above
    	        return (
    		      &lt;tr key={this.props.myKey + index.toString()}&gt;
    		        &lt;td&gt;&lt;img src={item.image} alt={item.name} width=&quot;50&quot;/&gt; {item.name}&lt;/td&gt;
    		        &lt;td&gt;{item.selectedOption}&lt;/td&gt;
    		      &lt;/tr&gt;
    		    )
    		  }
            })}
          &lt;/div&gt;
        )
      }
    }


Is there a way I can return those multiple rows and have them be in the same table without wrapping them in a div and getting an error?  I realize I can make a separate table for each component, but that throws my formatting off a bit.

How do I wrap a React component that returns multiple table rows and avoid the &quot;&lt;tr&gt; cannot appear as a child of &lt;div&gt;&quot; error?

I am starting my project with Angular2 and the developers seem to recommend RXJS Observable instead of Promises.

I have achieved to retrieve a list of elements (epics) from the server.
But how can I filter the elments by using for example an id?

The following code is an extraction from my app and shows now the final working solution. Let&#39;s hope it helps someone.



	@Injectable()
	export class EpicService {

	  private url = CONFIG.SERVER + &#39;/app/&#39;;  // URL to web API

	  constructor(private http:Http) {}

	  private extractData(res:Response) {
		let body = res.json();
		return body;
	  }

	  getEpics():Observable&lt;Epic[]&gt; {
		return this.http.get(this.url + &quot;getEpics&quot;)
		  .map(this.extractData)
		  .catch(this.handleError);
	  }
	  
	  getEpic(id:string): Observable&lt;Epic&gt; {
		return this.getEpics()
		  .map(epics =&gt; epics.filter(epic =&gt; epic.id === id)[0]);
	  }
	}

	export class EpicComponent {

	  errorMessage:string;
	  epics:Epic[];
	  epic:Epic;

	  constructor(
		private requirementService:EpicService) {
	  }

	  getEpics() {
		this.requirementService.getEpics()
		  .subscribe(
			epics =&gt; this.epics = epics,
			error =&gt; this.errorMessage = &lt;any&gt;error);
	  }
	  
	  // actually this should be eventually in another component
	  getEpic(id:string) {
		this.requirementService.getEpic(id)
			.subscribe(
			epic =&gt; this.epic = epic,
			error =&gt; this.errorMessage = &lt;any&gt;error);
	  }
	}

	export class Epic {
	  id: string;
	  name: string;
	}

Thank you in advance for your help.

Simple filter on array of RXJS Observable

I have an input:
```html
&lt;input 
  type=&quot;text&quot; 
  id=&quot;name&quot; 
  class=&quot;form-control&quot; 
  name=&quot;name&quot;  
  v-model=&quot;form.name&quot; 
  :disabled=&quot;validated ? &#39;&#39; : disabled&quot;
/&gt;
```
and in my Vue.js component, I have:
```js
..
..
ready() {
  this.form.name = this.store.name;
  this.form.validated = this.store.validated;
},
..
```

`validated` being a `boolean`, it can be either `0` or `1`, but no matter what value is stored in the database, my input is always disabled.

I need the input to be disabled if `false`, otherwise it should be enabled and editable.

Update:

Doing this always **enables** the input (no matter I have 0 or 1 in the database):
```js
&lt;input 
  type=&quot;text&quot; 
  id=&quot;name&quot; 
  class=&quot;form-control&quot; 
  name=&quot;name&quot; 
  v-model=&quot;form.name&quot; 
  :disabled=&quot;validated ? &#39;&#39; : disabled&quot;
/&gt;
```

Doing this always **disabled** the input (no matter I have 0 or 1 in  the database):
```js
&lt;input 
  type=&quot;text&quot; 
  id=&quot;name&quot; 
  class=&quot;form-control&quot; 
  name=&quot;name&quot; 
  v-model=&quot;form.name&quot; 
  :disabled=&quot;validated ? disabled : &#39;&#39;&quot;
/&gt;
```

Disable input conditionally (Vue.js)

I&#39;ve created a bot in telegram

I want to send bold and italic text with HTML page to bot

My HTML code is:

    &lt;html&gt;
    &lt;head&gt;&lt;title&gt;Telegram&lt;/title&gt;&lt;/head&gt;
    &lt;body&gt;
    	&lt;form method=&quot;GET&quot; action=&quot;https://api.telegram.org/bot(token)/sendMessage&quot;&gt;
    		&lt;input type=&quot;hidden&quot; name=&quot;chat_id&quot; value=&quot;@testadminch&quot;&gt;
    		&lt;input type=&quot;hidden&quot; name=&quot;parse_mod&quot; value=&quot;markdown&quot;&gt;
    		&lt;textarea name=&quot;text&quot;&gt;&lt;/textarea&gt;
    		&lt;input type=&quot;submit&quot; value=&quot;Submit&quot;&gt;
    	&lt;/form&gt;
    &lt;/body&gt;
    &lt;/html&gt;

If I send `*bold*` the output should be **bold** but it doesn&#39;t work


send bold &amp; italic text on telegram bot with html

A `script` element that got styled as `display:block` appears visible. Why is it possible and is there any real use case where it is desired?

&lt;!-- begin snippet: js hide: false console: true babel: false --&gt;

&lt;!-- language: lang-css --&gt;

    td &gt; * {
      display: block;
    }

&lt;!-- language: lang-html --&gt;

    &lt;table&gt;
      &lt;tr&gt;
        &lt;td&gt;
          &lt;script type=&quot;text/javascript&quot;&gt;
            var test = 1;
          &lt;/script&gt;von 1
        &lt;/td&gt;
      &lt;/tr&gt;
    &lt;/table&gt;

&lt;!-- end snippet --&gt;



When should &lt;script&gt; tags be visible and why can they?

`backdrop-filter` is a recent CSS feature, that is not yet available in modern browsers (at least as of July 1, 2016). 

+ Chrome 51 supports `backdrop-filter` via Experimental Web Platform flag.
+ Safari 9.1 supports it with `-webkit-` prefix
+ Firefox 47 have no support

Being in such an unusable state, I would like to know whether there exists any alternative way to bring in the same result.

JS workarounds for `blur`, `grayscale`,… are also welcome

The development of `backdrop-filter` can be tracked through https://bugs.chromium.org/p/chromium/issues/detail?id=497522

CSS: Workaround to backdrop-filter?

trying to get a form set up but for some reason, the Date input in my html is not binding to the object&#39;s date value, despite using [(ngModel)]

html:

    &lt;input type=&#39;date&#39; #myDate [(ngModel)]=&#39;demoUser.date&#39;/&gt;&lt;br&gt;

form component:

    export class FormComponent {
        demoUser = new User(0, &#39;&#39;, &#39;&#39;, &#39;&#39;, &#39;&#39;, new Date(), &#39;&#39;, 0, [], []);  
    }

User class: 

    export class User {
        constructor (
            public id: number,
            public email: string,
            public password: string,
            public firstName: string,
            public lastName: string,
            public date: Date,
            public gender: string,
            public weight: number,
            public dietRestrictions: string[],
            public fitnessGoals: string[]
        ){
            
        }
    }

A test output reveals the current &quot;new&quot; Date as the object&#39;s value, but the input doesn&#39;t update the User object&#39;s date value or reflect the value, suggesting neither of the two-way bindings are working. Help would be greatly appreciated.

Content Type	Original Author	Original Content on Stackoverflow
Question	Ender Che	View Question on Stackoverflow
Solution 1 - Javascript	TimoStaudinger	View Answer on Stackoverflow
Solution 2 - Javascript	BenAlabaster	View Answer on Stackoverflow
Solution 3 - Javascript	Kairat	View Answer on Stackoverflow

Error message ".innerHTML is not a function"

Javascript Problem Overview

Javascript Solutions

Solution 1 - Javascript

Solution 2 - Javascript

Solution 3 - Javascript

App crashing when using Firebase Auth, reason: 'Default app has already been configured.'

How to construct a std::string with embedded values, i.e. "string interpolation"?

Attributions