You can use `as` like this:



&lt;!-- language: lang-js --&gt;

    import {Class1} from &#39;../location1/class1&#39;
    import {Class1 as Alias} from &#39;../location2/class1&#39;

&lt;!-- end snippet --&gt;

You can find more about the ES6 import statement [here][1].


  [1]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/import

I need to store data in the browser&#39;s session and retrieve the data until the session exits. How&#160;do you use local and session storage in Angular 2?

How to use Local storage in Angular

Sometimes there is some non-critical asynchronous operation that needs to happen but I don&#39;t want to wait for it to complete.  In Tornado&#39;s coroutine implementation you can &quot;fire &amp; forget&quot; an asynchronous function by simply ommitting the `yield` key-word.

I&#39;ve been trying to figure out how to &quot;fire &amp; forget&quot; with the new `async`/`await` syntax released in Python 3.5.  E.g., a simplified code snippet:

&lt;!-- language: lang-python --&gt;

    async def async_foo():
        print(&quot;Do some stuff asynchronously here...&quot;)
    
    def bar():
        async_foo()  # fire and forget &quot;async_foo()&quot;
    
    bar()


What happens though is that `bar()` never executes and instead we get a runtime warning:

&lt;!-- language: lang-python --&gt;

    RuntimeWarning: coroutine &#39;async_foo&#39; was never awaited
      async_foo()  # fire and forget &quot;async_foo()&quot;



&quot;Fire and forget&quot; python async/await

In typescript, using Angular 2, I need to import two classes with the same name, but lying in different paths.

The project is quite too big that I find it hard to change the exported class names.

Is there any way to alias the imported classes,

    import {Class1} from &#39;../location1/class1&#39;
    import {Class1} from &#39;../location2/class1&#39;

Import two exported classes with the same name

In typescript, using Angular 2, I need to import two classes with the same name, but lying in different paths.
The project is quite too big that I find it hard to change the exported class names.
Is there any way to alias the imported classes,
<pre><code class="hljs language-javascript">import {Class1} from '../location1/class1'
import {Class1} from '../location2/class1'
</code></pre>

I am trying to build a simple blog with Angular 2 and Firebase and I am having issues using async pipe in a component. I get the error in the console.

&gt; zone.js:344Unhandled Promise rejection: Template parse errors:
&gt; The pipe &#39;async&#39; could not be found (&quot;
&gt; &lt;/p&gt;
&gt;
&gt; &lt;p&gt;[ERROR -&gt;]{{ (blog.user | async)?.first_name }}&lt;/p&gt;
&gt;
&gt; &quot;): BlogComponent@6:3 ; Zone: &lt;root&gt; ; Task: Promise.then ; Value: Error: Template parse errors:(…) Error: Template parse errors:
&gt; The pipe &#39;async&#39; could not be found (&quot;
&gt; &lt;/p&gt;

blog.component.ts

&lt;!-- language: lang-ts --&gt;

    import {Component, Input} from &quot;@angular/core&quot;;
    
    @Component({
      selector: &#39;blog-component&#39;,
      templateUrl: &#39;./blog.component.html&#39;,
      styleUrls: [&#39;./blog.component.css&#39;],
    })
    
    export class BlogComponent {
      @Input() blog;
    }

blog.component.html

&lt;!-- language: lang-html --&gt;

    &lt;h1 class=&quot;article-title&quot;&gt;{{ blog.title }}&lt;/h1&gt;
    &lt;p&gt;{{ (blog.user | async)?.first_name }}&lt;/p&gt;

app.component.ts

&lt;!-- language: lang-ts --&gt;

    import { Component } from &#39;@angular/core&#39;;
    import { BlogService } from &quot;./services/services.module&quot;;
    
    @Component({
      selector: &#39;app-root&#39;,
      templateUrl: &#39;./app.component.html&#39;,
      styleUrls: [&#39;./app.component.css&#39;]
    })
    
    export class AppComponent {
      constructor(private blogService: BlogService) {}
      articles = this.blogService.getAllArticles();
    }

app.component.html

&lt;!-- language: lang-html --&gt;

    &lt;article *ngFor=&quot;let article of articles | async&quot;&gt;
      &lt;blog-component [blog]=&quot;article&quot;&gt;&lt;/blog-component&gt;
    &lt;/article&gt;

blog.service.ts

&lt;!-- language: lang-ts --&gt;

    import {Injectable} from &quot;@angular/core&quot;;
    import {AngularFire} from &quot;angularfire2&quot;;
    import {Observable} from &quot;rxjs&quot;;
    import &quot;rxjs/add/operator/map&quot;;
    
    @Injectable()
    export class BlogService {
      constructor(private af: AngularFire) { }
    
      getAllArticles(): Observable&lt;any[]&gt; {
        return this.af.database.list(&#39;articles&#39;, {
          query: {
            orderByKey: true,
            limitToLast: 10
          }
        }).map((articles) =&gt; {
          return articles.map((article) =&gt; {
            article.user = this.af.database.object(`/users/${article.user_id}`);
            return article;
          });
        });
      }
    }

The problem arises only when I try to use async in blog.component.html file. It works if I try to print the user name in app.component.html file. Should I be injecting AsyncPipe in blog.module.ts? How can I get the async working in blog.component.ts?

The pipe &#39;async&#39; could not be found

I have an angular 2 service that fetch data from an API
this service has 3 subscribers (defined in Components) each doing something else with the data (different graphs)

I&#39;m noticing that I&#39;m doing three GET requests to the API while what i want to achieve is one request and that the subscribers will share the data
I&#39;ve looks into HOT and COLD observable and tried the .share() on the observable but I&#39;m still doing 3 individual calls

Update, adding code

&gt; Service

&lt;!-- language: lang-ts --&gt;

    import { Injectable } from &#39;@angular/core&#39;;
    import { Http, Response } from &#39;@angular/http&#39;;
    
    import {Observable} from &#39;rxjs/Rx&#39;;
    
    // Import RxJs required methods
    import &#39;rxjs/add/operator/map&#39;;
    import &#39;rxjs/add/operator/catch&#39;;
    
    import { StationCompliance } from &#39;./model/StationCompliance&#39;;
    
    
    @Injectable()
    export class StationComplianceService {
    
      private url = &#39;/api/read/stations&#39;;
    
      constructor(private http : Http) {
        console.log(&#39;Started Station compliance service&#39;);
       }
    
       getStationCompliance() : Observable&lt;StationCompliance []&gt; {
         return this.http.get(this.url)
          .map((res:Response) =&gt; res.json())
          .catch((error:any) =&gt; Observable.throw(error.json().error || &#39;Server Error&#39;));
       }
    }

&gt; Component 1

&lt;!-- language: lang-ts --&gt;

    import { Component, OnInit } from &#39;@angular/core&#39;;
    import { CHART_DIRECTIVES } from &#39;angular2-highcharts&#39;;
    
    import { StationComplianceService } from &#39;../station-compliance.service&#39;;
    
    
    @Component({
      selector: &#39;app-up-down-graph&#39;,
      templateUrl: &#39;./up-down-graph.component.html&#39;,
      styleUrls: [&#39;./up-down-graph.component.css&#39;]
    })
    export class UpDownGraphComponent implements OnInit {
    
      graphData;
    
      errorMessage: string;
    
      options;
    
      constructor(private stationService : StationComplianceService) { }
    
      ngOnInit() {
        this.getStationTypes();
      }
    
      getStationTypes(){
        this.stationService.getStationCompliance()
          .subscribe(
            graphData =&gt; {
              this.graphData = graphData;
              this.options = {
                chart : {type: &#39;pie&#39;,
                        plotShadow: true
                },
                plotOptions : {
                  showInLegend: true
                },
                title : {text: &#39;Up and Down devices&#39;},
                series: [{
                  data: this.processStationType(this.graphData)
                }]
              }
            },
            error =&gt; this.errorMessage = &lt;any&gt;error
          );
      }

Other two components are almost the same, they just show other graph

Angular 2 Observable with multiple subscribers

My problem, that when I use innererHtml binding  - angular2 remove all styles attributes. It&#39;s important for me, bacause in my task - html is generated on server-side with all styles.
Example:

&lt;!-- language: lang-typescript --&gt;

    @Component({
      selector: &#39;my-app&#39;,
      template: `
        &lt;input type=&quot;text&quot; [(ngModel)]=&quot;html&quot;&gt;
        &lt;div [innerHtml]=&quot;html&quot;&gt;
        &lt;/div&gt;
      `,
    })
    export class App {
      name:string;
      html: string;
      constructor() {
        this.name = &#39;Angular2&#39;
        this.html = &quot;&lt;span style=\&quot;color:red;\&quot;&gt;1234&lt;/span&gt;&quot;;
      }
    }

But in DOM I see only &lt;span&gt;1234&lt;span&gt; and this text is not red.

http://plnkr.co/edit/UQJOFMKl9OwMRIJ38U8D?p=preview

Thank you!

Angular2 innerHtml binding remove style attribute

    &lt;div&gt;
       &lt;input #ipt type=&quot;text&quot;/&gt;
    &lt;/div&gt;

Is it possible to access the template access variable from the component class?

i.e., can I access it here,

    class XComponent{
       somefunction(){
           //Can I access #ipt here?
       }
    }

Access template reference variables from component class

I&#39;ve got Angular [reactive form][1]. I created `formControl`s and assigned it to input fields by`[formControl]=...`. As I understand it creates `nativeElement &lt;-&gt; formControl` link.

My question: is it possible to get `nativeElement` for `formControl`? I want to do something like `myFormControl.nativeElement.focus()`


  [1]: https://angular.io/docs/ts/latest/cookbook/dynamic-form.html

Is it possible to get native element for formControl?

How can I declare a `class` type, so that I ensure the object is a constructor of a general class? 

In the following example, I want to know which type should I give to `AnimalClass` so that it could either be `Penguin` or `Lion`:


    class Animal {
        constructor() {
            console.log(&quot;Animal&quot;);
        }
    }
    
    class Penguin extends Animal {
        constructor() {
            super();
            console.log(&quot;Penguin&quot;);
        }
    }
    
    class Lion extends Animal {
        constructor() {
            super();
            console.log(&quot;Lion&quot;);
        }
    }
    
    class Zoo {
        AnimalClass: class // AnimalClass could be &#39;Lion&#39; or &#39;Penguin&#39;
        
        constructor(AnimalClass: class) {
            this.AnimalClass = AnimalClass
            let Hector = new AnimalClass();
        }
    }

Of course, the `class` type does not work, and it would be too general anyway.

Class constructor type in typescript?

How can I tell what version of TypeScript is being used in Visual Studio Code?  In particular, I had been using TypeScript 1.8.10 and VSCode 1.4.0.  I first updated VSCode to the latest version, which was 1.5.3.  But checking from the command line, I saw that my TypeScript version was still 1.8.10.  So I updated TypeScript from the command line, and it is now 2.0.3 .

Is there a way to tell for sure whether Visual Studio Code is using version 2.0.3?

Is there a method for updating Visual Studio Code that will automatically update TypeScript to the latest released version, or does the TypeScript update have to be done independently?

What TypeScript version is Visual Studio Code using? How to update it?

This

    const { foo: IFoo[] } = bar;

and this

    const { foo: Array&lt;IFoo&gt; } = bar;

will reasonably cause an error.

And this

    const { foo: TFoo } = bar;

will just destructure `TFoo` property.

How can types be specified for destructured object properties?

Types in object destructuring

Currently I have TypeScript 1.0.3.0 version installed on my machine.  
I want to update it to latest one i.e. 2.0.

How to do this with npm?

How to update TypeScript to latest version with npm?

I want to convert current data into `&#39;yyyy-MM-dd&#39;` format in .ts file. i template it can easily be done by using data pipe. how to do that in typescript.

**In template:**

    {{date  | date:&#39;yyyy-MM-dd&#39;}}

**How to convert in this format `&#39;yyyy-MM-dd&#39;` in typescript**.

now i am just getting current date by using this.

  

    this.date =  new Date();

but need to convert it into given format.
Please guide how to do that... Thanks!





How to convert date into this &#39;yyyy-MM-dd&#39; format in angular 2

In Ionic 2, I would like to access the `$colors` variables from the file &quot;[my project]\src\theme\variables.scss&quot;.

This file contains:

    $colors: (
      primary:    #387ef5,
      secondary:  #32db64,
      danger:     #f53d3d,
      light:      #f4f4f4,
      dark:       #222,
      favorite:   #69BB7B
    );

In a component, I draw a canvas. It looks like that:

    import {Component, Input, ViewChild, ElementRef} from &#39;@angular/core&#39;;
    
    @Component({
        selector: &#39;my-graph&#39;,
    })
    @View({
        template: `&lt;canvas #myGraph class=&#39;myGraph&#39;
         [attr.width]=&#39;_size&#39;
         [attr.height]=&#39;_size&#39;&gt;&lt;/canvas&gt;`,
    })
    
    export class MyGraphDiagram {
        private _size: number;
    
        // get the element with the #myGraph on it
        @ViewChild(&quot;myGraph&quot;) myGraph: ElementRef; 
    
        constructor(){
            this._size = 150;
        }
    
        ngAfterViewInit() { // wait for the view to init before using the element
    
          let context: CanvasRenderingContext2D = this.myGraph.nativeElement.getContext(&quot;2d&quot;);
          // HERE THE COLOR IS DEFINED AND I D LIKE TO ACCESS variable.scss TO DO THAT
          context.fillStyle = &#39;blue&#39;;
          context.fillRect(10, 10, 150, 150);
        }
    
    }

As one can see, at some point in this code the color of the shape is defined:          `context.fillStyle = &#39;blue&#39;` , I would like to use instead something like `context.fillStyle = &#39;[variables.scss OBJECT].$colors.primary &#39;`.

Has anyone an idea?
 

access SASS values ($colors from variables.scss) in Typescript (Angular2 ionic2)

I just set up my first ionic 2 app (I&#39;ve used ionic 1 fairly extensively). I&#39;m trying to use the [ionic-native camera](http://ionicframework.com/docs/v2/native/camerapreview/) preview plugin.

**The setup was pretty straight forward:**

    npm install -g ionic cordova
    ionic start timesnap --v2
    ionic platform add android
    ionic platform add ios
    ionic plugin add cordova-plugin-camera-preview --save

**Then I copied and pasted the example code into the about page:**

    import { CameraPreview, CameraPreviewRect } from &#39;ionic-native&#39;;
    
    // camera options (Size and location)
    let cameraRect: CameraPreviewRect = {
      x: 100,
      y: 100,
      width: 200,
      height: 200
    };
    
    
    // start camera
    CameraPreview.startCamera(
      cameraRect, // position and size of preview
      &#39;front&#39;, // default camera
      true, // tap to take picture
      false, // disable drag
      true, // send the preview to the back of the screen so we can addoverlaying elements
      1 //alpha
    );

**I launched the app using the following commands:**

    ionic emulate android -lcs
    
    ionic emulate ios -lcs --target=&#39;iPhone-6&#39;

At first the camera just wasn&#39;t showing up then I ran `chrome://inspect` and saw warnings about Cordova missing &quot;try running in an emulator&quot;, but this was while running in an android emulator. I tried iOS too and saw the same results.

Any ideas why cordova isn&#39;t loading?

Here is the full error log from `chrome://inspect` while running in an android emulator:

[![enter image description here][1]][1]


  [1]: https://i.stack.imgur.com/p9FPq.png

**Update... index.html**

(it&#39;s just the standard one generated by ionic)


    &lt;!DOCTYPE html&gt;
    &lt;html lang=&quot;en&quot; dir=&quot;ltr&quot;&gt;
    &lt;head&gt;
      &lt;meta charset=&quot;UTF-8&quot;&gt;
      &lt;title&gt;Ionic App&lt;/title&gt;
      &lt;meta name=&quot;viewport&quot; content=&quot;width=device-width, initial-scale=1.0, minimum-scale=1.0, maximum-scale=1.0, user-scalable=no&quot;&gt;
      &lt;meta name=&quot;format-detection&quot; content=&quot;telephone=no&quot;&gt;
      &lt;meta name=&quot;msapplication-tap-highlight&quot; content=&quot;no&quot;&gt;
    
      &lt;link rel=&quot;icon&quot; type=&quot;image/x-icon&quot; href=&quot;assets/icon/favicon.ico&quot;&gt;
      &lt;link rel=&quot;manifest&quot; href=&quot;manifest.json&quot;&gt;
      &lt;meta name=&quot;theme-color&quot; content=&quot;#4e8ef7&quot;&gt;
      
      &lt;!-- cordova.js required for cordova apps --&gt;
      &lt;script src=&quot;cordova.js&quot;&gt;&lt;/script&gt;
    
      &lt;!-- un-comment this code to enable service worker
      &lt;script&gt;
        if (&#39;serviceWorker&#39; in navigator) {
          navigator.serviceWorker.register(&#39;service-worker.js&#39;)
            .then(() =&gt; console.log(&#39;service worker installed&#39;))
            .catch(err =&gt; console.log(&#39;Error&#39;, err));
        }
      &lt;/script&gt;--&gt;
    
      &lt;link href=&quot;build/main.css&quot; rel=&quot;stylesheet&quot;&gt;
    
    &lt;/head&gt;
    &lt;body&gt;
    
      &lt;!-- Ionic&#39;s root component and where the app will load --&gt;
      &lt;ion-app class=&quot;trans&quot;&gt;&lt;/ion-app&gt;
    
      &lt;!-- The polyfills js is generated during the build process --&gt;
      &lt;script src=&quot;build/polyfills.js&quot;&gt;&lt;/script&gt;
    
      &lt;!-- The bundle js is generated during the build process --&gt;
      &lt;script src=&quot;build/main.js&quot;&gt;&lt;/script&gt;
    
    &lt;/body&gt;
    &lt;/html&gt;



Ionic 2: Cordova is not available. Make sure to include cordova.js or run in a device/simulator (running in emulator)

I want to iterate [object object] using *ngFor in Angular 2. &lt;br&gt;&lt;br&gt;The problem is the object is not array of object but object of object which contains further objects.

    {
    
      &quot;data&quot;: {
        &quot;id&quot;: 834,
        &quot;first_name&quot;: &quot;GS&quot;,
        &quot;last_name&quot;: &quot;Shahid&quot;,
        &quot;phone&quot;: &quot;03215110224&quot;,
        &quot;role&quot;: null,
        &quot;email&quot;: &quot;test@example.com&quot;,
        &quot;picture&quot;: **{ &lt;-- I want to get thumb: url but not able to fetch that**
          &quot;url&quot;: null,
          &quot;thumb&quot;: {
            &quot;url&quot;: null
          }
        },
        &quot;address&quot;: &quot;Nishtar Colony&quot;,
        &quot;city_id&quot;: 2,
        &quot;provider&quot;: &quot;email&quot;,
        &quot;uid&quot;: &quot;test@example.com&quot;
      }
    }

I know we can use pipe to iterate the object but how we can iterate further from object to object means **data-&gt;picture-&gt;thum:url**.


 

How to iterate object keys using *ngFor

I am trying to access the value of the input file from my ionic 2 application but still I&#39;m facing the issue of property files does not exist on type &#39;EventTarget&#39;.
As it is properly working in js but not in typescript.
The code is given below:

      document.getElementById(&quot;customimage&quot;).onchange= function(e?) {
                var files: any = e.target.files[0]; 
                  EXIF.getData(e.target.files[0], function() {
                      alert(EXIF.getTag(this,&quot;GPSLatitude&quot;));
                  });
              }

Please help me solve this issue as it is not building my ionic 2 application. 

Content Type	Original Author	Original Content on Stackoverflow
Question	Rizan Zaky	View Question on Stackoverflow
Solution 1 - Angular	toskv	View Answer on Stackoverflow

Import two exported classes with the same name

Angular Problem Overview

Angular Solutions

Solution 1 - Angular

"Fire and forget" python async/await

How to use Local storage in Angular

Attributions