For a single style attribute, you can use the following syntax:
```html
&lt;div [style.background-color]=&quot;style1 ? &#39;red&#39; : (style2 ? &#39;blue&#39; : null)&quot;&gt;
```
I assumed that the background color should not be set if neither `style1` nor `style2` is `true`.

&lt;hr/&gt;

Since the question title mentions `ngStyle`, here is the equivalent syntax with that directive:

```html
&lt;div [ngStyle]=&quot;{&#39;background-color&#39;: style1 ? &#39;red&#39; : (style2 ? &#39;blue&#39; : null) }&quot;&gt;
```

You can use an inline if inside your ngStyle:

    [ngStyle]=&quot;styleOne?{&#39;background-color&#39;: &#39;red&#39;} : {&#39;background-color&#39;: &#39;blue&#39;}&quot;

A batter way in my opinion is to store your background color inside a variable and then set the background-color as the variable value:

    [style.background-color]=&quot;myColorVaraible&quot;

    [ngStyle]=&quot;{&#39;opacity&#39;: is_mail_sent ? &#39;0.5&#39; : &#39;1&#39; }&quot;

    &lt;ion-col size=&quot;12&quot;&gt;
      &lt;ion-card class=&quot;box-shadow ion-text-center background-size&quot;
      *ngIf=&quot;data != null&quot;
      [ngStyle]=&quot;{&#39;background-image&#39;: &#39;url(&#39; + data.headerImage + &#39;)&#39;}&quot;&gt;
      
      &lt;/ion-card&gt;

    [ngStyle]=&quot;{ &#39;top&#39;: yourVar === true ? widthColumHalf + &#39;px&#39;: &#39;302px&#39; }&quot;

When l try to use `git push`, an error reports: 

&gt; Fatal: fatal: unable to access &#39;https://github.com/xxx&#39;: OpenSSL
&gt; SSL_connect: SSL_ERROR_SYSCALL in connection to github.com:443

My git version is 2.16.2 for windows

It worked well before this day, and reinstalling git seems to not work.

Can anyone help me with that? Thanks in advance!



fatal: unable to access &#39;https://github.com/xxx&#39;: OpenSSL SSL_connect: SSL_ERROR_SYSCALL in connection to github.com:443

I am using the `Angular-CLI 1.6.6` and `@angular/service-worker 5.2.5` in our `Angular 5.2.5` app. Everything works fine on the local lite-server, as well as on the production server, except for one error message popping in our production environment: 

&gt; Failed to load resource: the server responded with a status of 504
&gt; (Gateway Timeout)

Looking into the `ngsw-worker.js` script I found the lines (2466 following) where the error message above is generated:

```typescript
    async safeFetch(req) {
        try {
            return await this.scope.fetch(req);
        }
        catch (err) {
            this.debugger.log(err, `Driver.fetch(${req.url})`);
            return this.adapter.newResponse(null, {
                status: 504,
                statusText: &#39;Gateway Timeout&#39;,
            });
        }
    } 
```
Console logging err in the catch puts out the following error:
```bash
    TypeError: Failed to execute &#39;fetch&#39; on &#39;ServiceWorkerGlobalScope&#39;: &#39;only-if-cached&#39; can be set only with &#39;same-origin&#39; mode
        at Driver.safeFetch (ngsw-worker.js:2464)
        at Driver.handleFetch (ngsw-worker.js:1954)
        at &lt;anonymous&gt;
```
An error that seems related to this question: https://stackoverflow.com/questions/48463483/what-causes-a-failed-to-execute-fetch-on-serviceworkerglobalscope-only-if

The req that generates this error is any first access to the app:

    https://example.com/test/#/connect
    https://example.com/test/#/map?token=[accestoken]
    ...

On app reload the error is not repeated.

Can anybody help me out here? Is there a bug in `safeFetch()` of the service worker (maybe to support HashLocationStrategy)? Do I have to change anything in my config?

Angular Service Worker - Failed to load resource: the server responded with a status of 504 (Gateway Timeout)

I have a div that I want to style based on a condition.

If styleOne is true I want a background colour of red. If StyleTwo is true, I want the background colour to be blue. I&#39;ve got half of it working with the below code.
```html
    &lt;div id=&quot;myDiv&quot; [ngStyle]=&quot;styleOne &amp;&amp; {&#39;background-color&#39;: &#39;red&#39;}&quot;&gt;
```
Is it possible to add a condition to say:

- if styleOne is true, do this
- if styleTwo is true, do this?


**Edit**

I think i&#39;ve resolved it. It works. Not sure if it&#39;s the best way:
```html
&lt;div id=&quot;div&quot; [ngStyle]=&quot;styleOne &amp;&amp; {&#39;background-color&#39;: &#39;red&#39;} || styleTwo &amp;&amp; {&#39;background-color&#39;: &#39;blue&#39;}&quot;&gt;
```

Angular - How to apply [ngStyle] conditions

I have a div that I want to style based on a condition.
If styleOne is true I want a background colour of red. If StyleTwo is true, I want the background colour to be blue. I've got half of it working with the below code.
<pre><code class="hljs language-css"> &#x3C;div id="myDiv" [ngStyle]="styleOne &#x26;&#x26; {'background-color': 'red'}">
</code></pre>
Is it possible to add a condition to say:
<ul>
<li>if styleOne is true, do this</li>
<li>if styleTwo is true, do this?</li>
</ul>
Edit
I think i've resolved it. It works. Not sure if it's the best way:
<pre><code class="hljs language-css">&#x3C;div id="div" [ngStyle]="styleOne &#x26;&#x26; {'background-color': 'red'} || styleTwo &#x26;&#x26; {'background-color': 'blue'}">
</code></pre>

In a project of mine, I try to display Angular Components (like an Autocomplete Dropdown Search) in a table. Because of the requirements I have (like multi-selecting different cells with &lt;kbd&gt;ctrl&lt;/kbd&gt;+click) I decided to give it a go with handsontable.

I&#39;ve used the [handsontable renderer][1] and [add the components dynamically][2].

The code looks like this

matrix.component.ts
```typescript
this.hot = new Handsontable(this.handsontable.nativeElement, {
  data: this.tableData,
  colWidths: [80, 300],
  colHeaders: [&#39;Id&#39;, &#39;Custom Component&#39;],
  columns: [
    {
      data: &#39;id&#39;,
    },
    {
      data: &#39;id&#39;,
      renderer: (instance: any, td: any, row: any, col: any, prop: any, value: any, cellProperties: any) =&gt; {
        if (cellProperties.hasOwnProperty(&#39;ref&#39;)) {
          (cellProperties.ref as ComponentRef&lt;CellContainerComponent&gt;).instance.value = row;
        } else {
          cellProperties.ref = this.loadComponentAtDom(
            CellContainerComponent,
            td,
            ((component: any) =&gt; {
              component.template = this.button4Matrix;
              component.value = row;
            }));
        }
        return td;
      },
      readOnly: true,
    },
  ],
});


private loadComponentAtDom&lt;T&gt;(component: Type&lt;T&gt;, dom: Element, onInit?: (component: T) =&gt; void): ComponentRef&lt;T&gt; {
  let componentRef;
  try {
    const componentFactory = this.componentFactoryResolver.resolveComponentFactory(component);
    componentRef = componentFactory.create(this.injector, [], dom);
    onInit ? onInit(componentRef.instance) : console.log(&#39;no init&#39;);
    this.appRef.attachView(componentRef.hostView);
  } catch (e) {
    console.error(&#39;Unable to load component&#39;, component, &#39;at&#39;, dom);
    throw e;
  }
  return componentRef;
}
```
What&#39;s my current issue is the lifecycle of the rendered angular components.


Stuff I tried:

1. **Do nothing**

*Tried Solution*: Doing nothing and leaving everything to Angular

*Problem*: Angular never calling the ngOnDestroy of the CellContainer.



 
2. **Saving componentRefs**

*Tried Solution*: Saving the componentRef in an Array and after a certain amount of rendering trying to destroy the components I
    rendered some time ago. Counting via time, handsontable hooks
    (verticalScroll/beforeRender/afterRender), in the render-method

*Problem*: Destroy of the angular component always throws an error (&#39;cannot read property&#39;nativeNode&#39; of null&#39;) or the components get
    displayed completely wrong
    


3. **Check during rendering if an element is there**

*Tried Solution*: During the render: I checked if there&#39;s already a component and if it was I used to recycle the already-there component by adding a new value only.

*Problem*: The values get completely mixed up during scrolling.

A link to my solution (and an implemented solution #3) is available on [github][3].

Does anyone have an idea of how to handle this in a clean way? If not the application gets slow &amp; unusable after a little bit of scrolling &amp; using the table.
Better refer : [https://handsontable.com/docs/8.2.0/tutorial-cell-function.html][4]


  [1]: https://docs.handsontable.com/pro/1.18.0/demo-custom-renderers.html
  [2]: https://medium.com/front-end-hacking/dynamically-add-components-to-the-dom-with-angular-71b0cb535286
  [3]: https://github.com/phhbr/handsontable-filled-with-ng-components
  [4]: https://handsontable.com/docs/8.2.0/tutorial-cell-function.html

Rendering Angular components in Handsontable Cells

I have a problem with an unit test in angular 5 with Jasmine and Karma.

The error is: &quot;Can&#39;t bind to &#39;fruits&#39; since it isn&#39;t a known property of &#39;my-component2&#39;&quot;.

The unit test code is:

src/app/components/my-component1/my-component1.component.spec.ts:

&lt;!-- begin snippet: js hide: false console: true babel: false --&gt;

&lt;!-- language: lang-js --&gt;


    import { TestBed, inject, ComponentFixture, async} from &#39;@angular/core/testing&#39;;
    import {HttpClientTestingModule, HttpTestingController} from &#39;@angular/common/http/testing&#39;;

    import { Post } from &#39;../../models/post.model&#39;;

    import { MyComponent1Component } from &#39;./my-component1.component&#39;;
    import { MyService1Service } from &#39;../../services/my-service1.service&#39;;

    import { HttpClientModule, HttpClient,HttpHandler } from &#39;@angular/common/http&#39;;
    import {fruit} from &#39;../../Models/fruit&#39;;


    fdescribe(&#39;MyComponent1Component&#39;, () =&gt; {
      let component: MyComponent1Component;
      let fixture: ComponentFixture&lt;MyComponent1Component&gt;;

      beforeEach(async(() =&gt; {
        TestBed.configureTestingModule({
          declarations: [ MyComponent1Component ],
          imports: [],
          providers: [MyService1Service, HttpClient, HttpHandler, HttpTestingController]
        })

        .compileComponents();
      }));

      beforeEach(async(() =&gt; {
        fixture = TestBed.createComponent(MyComponent1Component);
        component = fixture.componentInstance;
        fixture.detectChanges();
      }));

      it(&#39;should create&#39;, () =&gt; {
        expect(component).toBeTruthy();
      });
    });


&lt;!-- end snippet --&gt;

And these are the code of my components:

src/app/components/my-component1/my-component1.component.ts:

&lt;!-- begin snippet: js hide: false console: true babel: false --&gt;

&lt;!-- language: lang-js --&gt;

    import { Component, OnInit } from &#39;@angular/core&#39;;
    import { MyService1Service} from &#39;../../services/my-service1.service&#39;;
    import {fruit} from &#39;../../Models/fruit&#39;;

    @Component({
      selector: &#39;my-component1&#39;,
      templateUrl: &#39;./my-component1.component.html&#39;,
      styleUrls: [&#39;./my-component1.component.css&#39;]
    })
    export class MyComponent1Component implements OnInit {

      constructor(private _MyService1Service: MyService1Service) { }

      public fruit= new fruit();

      public fruits: fruit[];
      ngOnInit() {
        this._MyService1Service.getPost().subscribe(
            result =&gt; {
                  console.log(result);
            },
            error =&gt; {
              console.log(&lt;any&gt;error);
            }
          );

        this.fruit.name = &#39;apple&#39;;
        this.fruits.push(this.fruit);
      }
    }




&lt;!-- end snippet --&gt;

src/app/components/my-component1/my-component1.component.html:

&lt;!-- begin snippet: js hide: false console: true babel: false --&gt;

&lt;!-- language: lang-html --&gt;

     &lt;p&gt;
          my-component1 works!
        &lt;/p&gt;

        &lt;my-component2 [fruits]=fruits&gt;&lt;/my-component2&gt;

&lt;!-- end snippet --&gt;

src/app/components/my-component2/my-component2.component.ts:

&lt;!-- begin snippet: js hide: false console: true babel: false --&gt;

&lt;!-- language: lang-js --&gt;

    import { Component, OnInit, Input } from &#39;@angular/core&#39;;
    import {fruit} from &#39;../../Models/fruit&#39;;

    @Component({
      selector: &#39;my-component2&#39;,
      templateUrl: &#39;./my-component2.component.html&#39;,
      styleUrls: [&#39;./my-component2.component.css&#39;]
    })
    export class MyComponent2Component implements OnInit {

      @Input() fruits: fruit[];

      constructor() { }

      ngOnInit() {
      }

    }


&lt;!-- end snippet --&gt;

src/app/components/my-component2/my-component2.component.html:

&lt;!-- begin snippet: js hide: false console: true babel: false --&gt;

&lt;!-- language: lang-html --&gt;

    &lt;p&gt;
      my-component2 works!
    &lt;/p&gt;


&lt;!-- end snippet --&gt;

It is a dummy project, can anybody help me?

Thanks :)


Unit test Angular with Jasmine and Karma, Error:Can&#39;t bind to &#39;xxx&#39; since it isn&#39;t a known property of &#39;xxxxxx&#39;.

I am trying to figure out how to use a pipe within a reactive form so that the input is forced into a currency format.  I have already created my own pipe for this which I have tested in other areas of the code so I know it works as a simple pipe.  My pipe name is &#39;udpCurrency&#39;

The closest answer I could find on stack overflow was this one: https://stackoverflow.com/questions/39642882/using-pipes-within-ngmodel-on-input-elements-in-angular2-view However this is not working in my case and I suspect it has something to do with the fact that my form is reactive

Here is all the relevant code:

**The Template**

    &lt;form [formGroup]=&quot;myForm&quot; #f=&quot;ngForm&quot;&gt;
      &lt;input class=&quot;form-control col-md-6&quot; 
        formControlName=&quot;amount&quot; 
        [ngModel]=&quot;f.value.amount | udpCurrency&quot; 
        (ngModelChange)=&quot;f.value.amount=$event&quot; 
        placeholder=&quot;Amount&quot;&gt;
    &lt;/form&gt;

**The component**

    import { Component, OnInit, HostListener } from &#39;@angular/core&#39;;
    import { FormBuilder, FormGroup, Validators } from &#39;@angular/forms&#39;;
    
    export class MyComponent implements OnInit {
      myForm: FormGroup;
    
      constructor(
        private builder: FormBuilder
      ) {
        this.myForm = builder.group({
          amount: [&#39;&#39;, Validators.required]
        });
      }    
    }

**The error:**

    ERROR Error: ExpressionChangedAfterItHasBeenCheckedError: Expression has changed after it was checked. Previous value: &#39;undefined: &#39;. Current value: &#39;undefined: undefined&#39;




How to use pipes in Angular 5 reactive form input

When I try to build my project running the following command:

&lt;!-- language-all: lang-none --&gt;
     
    ng build --environment=prod --aot=false  --output-path=&quot;...&quot; --base-href=&quot;...&quot;
You seem to not be depending on `@angular/core`.

This is an error, however, I don&#39;t understand why because before it worked well.

I tried to do this: 

&lt;!-- language-all: lang-none --&gt;

    npm install @angular/core 

But I get this error : 
    
&gt;`error     at Error (native)
error  { Error: EACCES: permission denied, chown &#39;&#39;
error     at Error (native)
error   errno: -13,
error   code: &#39;EACCES&#39;,
error   syscall: &#39;chown&#39;,
error Please try running this command again as root/Administrator.
verbose exit [ -13, true ]`

I also tried to get rid of `node_modules`, then make an install npm: but I get the same error.

And when I run the following command:

&lt;!-- language-all: lang-none --&gt;

    ng serve

I have another error:
                                                                                                            
&gt;`The &quot;@angular/compiler-cli&quot; package was not properly installed. Error: Error: Cannot find module &#39;@angular/compiler-cli&#39;`

This is my `package.json` :

&lt;!-- language-all: lang-json --&gt;

    &quot;ng&quot;: &quot;ng&quot;,
    &quot;start&quot;: &quot;ng serve&quot;,
    &quot;build&quot;: &quot;ng build&quot;,
    &quot;test&quot;: &quot;ng test&quot;,
    &quot;lint&quot;: &quot;ng lint&quot;,
    &quot;e2e&quot;: &quot;ng e2e&quot;
 
    &quot;@angular/animations&quot;: &quot;^4.0.0&quot;,
    &quot;@angular/common&quot;: &quot;^4.0.0&quot;,
    &quot;@angular/compiler&quot;: &quot;^4.0.0&quot;,
    &quot;@angular/core&quot;: &quot;^4.0.0&quot;,
    &quot;@angular/forms&quot;: &quot;^4.0.0&quot;,
    &quot;@angular/http&quot;: &quot;^4.0.0&quot;,
    &quot;@angular/platform-browser&quot;: &quot;^4.0.0&quot;,
    &quot;@angular/platform-browser-dynamic&quot;: &quot;^4.0.0&quot;,
    &quot;@angular/router&quot;: &quot;^4.0.0&quot;,
    &quot;@types/jquery&quot;: &quot;^3.2.17&quot;,
    &quot;cli-color&quot;: &quot;^1.2.0&quot;,
    &quot;core-js&quot;: &quot;^2.4.1&quot;,
    &quot;font-awesome&quot;: &quot;^4.7.0&quot;,
    &quot;jquery&quot;: &quot;^3.2.1&quot;,
    &quot;matrix-js-sdk&quot;: &quot;^0.8.5&quot;,
    &quot;moment&quot;: &quot;^2.18.1&quot;,
    &quot;olm&quot;: &quot;https://matrix.org/packages/npm/olm/olm-2.2.2.tgz&quot;,
    &quot;readline&quot;: &quot;^1.3.0&quot;,
    &quot;rxjs&quot;: &quot;^5.4.1&quot;,
    &quot;socket.io-client&quot;: &quot;^2.0.3&quot;,
    &quot;zone.js&quot;: &quot;^0.8.14&quot;
  
    &quot;@angular/cli&quot;: &quot;1.2.6&quot;,
    &quot;@angular/compiler-cli&quot;: &quot;^4.0.0&quot;,
    &quot;@angular/language-service&quot;: &quot;^4.0.0&quot;,
    &quot;@types/jasmine&quot;: &quot;~2.5.53&quot;,
    &quot;@types/jasminewd2&quot;: &quot;~2.0.2&quot;,
    &quot;@types/jquery&quot;: &quot;^3.2.17&quot;,
    &quot;@types/node&quot;: &quot;~6.0.60&quot;,
    &quot;codelyzer&quot;: &quot;~3.0.1&quot;,
    &quot;jasmine-core&quot;: &quot;~2.6.2&quot;,
    &quot;jasmine-spec-reporter&quot;: &quot;~4.1.0&quot;,
    &quot;karma&quot;: &quot;~1.7.0&quot;,
    &quot;karma-chrome-launcher&quot;: &quot;~2.1.1&quot;,
    &quot;karma-cli&quot;: &quot;~1.0.1&quot;,
    &quot;karma-coverage-istanbul-reporter&quot;: &quot;^1.2.1&quot;,
    &quot;karma-jasmine&quot;: &quot;~1.1.0&quot;,
    &quot;karma-jasmine-html-reporter&quot;: &quot;^0.2.2&quot;,
    &quot;protractor&quot;: &quot;~5.1.2&quot;,
    &quot;ts-node&quot;: &quot;~3.0.4&quot;,
    &quot;tslint&quot;: &quot;~5.3.2&quot;,
    &quot;typescript&quot;: &quot;~2.3.3&quot;



&quot;You seem to not be depending on &quot;@angular/core&quot;.&quot;

I am using angular 2 common http that return an Observable, but I face with a problem that my code likes a mesh when I use nested Observable call: 

    this.serviceA.get().subscribe((res1: any) =&gt; {
       this.serviceB.get(res1).subscribe((res2: any) =&gt; {
           this.serviceC.get(res2).subscribe((res3: any) =&gt; {
       
           })
       })
    })

Now I wanna use async/await to avoid that but async/await only work with Promise. I know that Observable can be converted to Promise but as I know, it is not a good practice. So what should I do here ?

BTW, it will be nice if anyone can give me an example code to solve this with async/await :D 

Content Type	Original Author	Original Content on Stackoverflow
Question	MegaTron	View Question on Stackoverflow
Solution 1 - Angular	ConnorsFan	View Answer on Stackoverflow
Solution 2 - Angular	Gili Yaniv	View Answer on Stackoverflow
Solution 3 - Angular	Apurv Chaudhary	View Answer on Stackoverflow
Solution 4 - Angular	fahimeh ahmadi	View Answer on Stackoverflow
Solution 5 - Angular	Ajay Kumar	View Answer on Stackoverflow

Angular - How to apply [ngStyle] conditions

Angular Problem Overview

Angular Solutions

Solution 1 - Angular

Solution 2 - Angular

Solution 3 - Angular

Solution 4 - Angular

Solution 5 - Angular

Angular Service Worker - Failed to load resource: the server responded with a status of 504 (Gateway Timeout)

fatal: unable to access 'https://github.com/xxx': OpenSSL SSL_connect: SSL_ERROR_SYSCALL in connection to github.com:443

Attributions