If possible update target to `es2015` (or above) in the tsconfig to resolve the error without enabling down level iteration`:

```
{
  &quot;compilerOptions&quot;: {
    &quot;target&quot;: &quot;es2015&quot;
  }
}
```

If you target es5, enable `downLevelIteration` explicitly in the tsconfig:

```
{
  &quot;compilerOptions&quot;: {
    &quot;target&quot;: &quot;es5&quot;,
    &quot;downlevelIteration&quot;: true
  }
}
```


    tsc demo.ts --lib &quot;es6&quot;,&quot;dom&quot; --downLevelIteration
    
Use this command for compilation. It will solve the issue. Adding these values in tsconfig.json will not solve the problem, if tsconfig.json is created with target:es5. updating tsconfig.json manually will not work. Use this command, just change the name of your .ts file.

Material Design for iOS doesn&#39;t look good, especially the **TextField**. So is there any way to create your own ? Or Is ther any way to add some styling to TextField so it will look rounded ?

How can I make rounded TextField in flutter?

I have made a certain app in Django, and I know that Django Rest Framework is used for building APIs. However, when I started to read about Django Rest Framework on their website, I noticed that each and every thing in [API Guide][1](like request, response, views etc.) claims it is superior to Django (request, response, views etc.).

The thing I am not understanding is whether these APIs will replace my existing Django models, views etc. or how can I use them differently in my existing Django code?


I am quite familiar with Django, but not able to understand exactly what Django Rest Framework is even after spending some time on it. (I know it is used for APIs.) Also, do I actually need an API? My app is able to send data to the server without an API, so in what case would I need an API?

  [1]: http://www.django-rest-framework.org/

Django or Django Rest Framework

When I use the [`yield*` expression](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/yield*) on TypeScript, it always gets an error.

&gt; Type &#39;IterableIterator&lt;T&gt;&#39; is not an array type.

How can I set the types correctly without using `any` to avoid the errors?


    function* g1(): IterableIterator&lt;number&gt; {
      yield 2;
      yield 3;
      yield 4;
    }
    
    function* g2(): IterableIterator&lt;number&gt; {
      yield 1;
      // ERROR: Type &#39;IterableIterator&lt;number&gt;&#39; is not an array type.
      yield* g1();
      yield 5;
    }
    
    const iterator = g2();


TypeScript and Iterator: Type &#39;IterableIterator&lt;T&gt;&#39; is not an array type

When I use the <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/yield*" target="_blank" rel="noopener noreferrer"><code>yield*</code> expression</a> on TypeScript, it always gets an error.
> Type 'IterableIterator<t>' is not an array type.</t>
How can I set the types correctly without using <code>any</code> to avoid the errors?
<pre><code class="hljs language-arduino">function* g1(): IterableIterator&#x3C;number> {
 yield 2;
 yield 3;
 yield 4;
}

function* g2(): IterableIterator&#x3C;number> {
 yield 1;
 // ERROR: Type 'IterableIterator&#x3C;number>' is not an array type.
 yield* g1();
 yield 5;
}

const iterator = g2();
</code></pre>

I have got a tslint error to my for loop when I try to resolve it it says to convert to for-of. I have seen many docs but its not helpful.How can I solve the lint error and I cannot do tslint:disable-next-line:prefer-for-of

    for (let i = 0; i &lt; this.rows.length; ++i) {
        if (!this.rows[i].selected) {
            this.selectAllChecked = false;
            break;
        }
    }



[tslint]Expected a &#39;for-of&#39; loop instead of a &#39;for&#39; loop with this simple iteration (prefer-for-of)

With TypeScript 2.7.2, in VSCode version 1.21 with @types/express and the code that follows, in some cases VSCode throws errors stating that 
```
A namespace-style import cannot be called or constructed, and will cause a failure at runtime.
``` 

However on other machines with similar setups and similar `tsconfig.json` files the code just works. What is happening here...

    import { Bank } from &#39;./Bank&#39;;
    import * as Express from &#39;express&#39;;  &lt;== errors here..
    
    let app: Express.Express;
    this.app = Express();                &lt;== and here


Why is this happening? 

TIA, 

John.


A namespace-style import cannot be called or constructed, and will cause a failure at runtime

I want to be able to assign an object property to a value given a key and value as inputs yet still be able to determine the type of the value. It&#39;s a bit hard to explain so this code should reveal the problem:


    type JWT = { id: string, token: string, expire: Date };
    const obj: JWT = { id: &#39;abc123&#39;, token: &#39;tk01&#39;, expire: new Date(2018, 2, 14) };

    function print(key: keyof JWT) {
        switch (key) {
            case &#39;id&#39;:
            case &#39;token&#39;:
                console.log(obj[key].toUpperCase());
                break;
            case &#39;expire&#39;:
                console.log(obj[key].toISOString());
                break;
        }
    }

    function onChange(key: keyof JWT, value: any) {
        switch (key) {
            case &#39;id&#39;:
            case &#39;token&#39;:
                obj[key] = value + &#39; (assigned)&#39;;
                break;
            case &#39;expire&#39;:
                obj[key] = value;
                break;
        }
    }

    print(&#39;id&#39;);
    print(&#39;expire&#39;);
    onChange(&#39;id&#39;, &#39;def456&#39;);
    onChange(&#39;expire&#39;, new Date(2018, 3, 14));
    print(&#39;id&#39;);
    print(&#39;expire&#39;);

    onChange(&#39;expire&#39;, 1337); // should fail here at compile time
    print(&#39;expire&#39;); // actually fails here at run time



I tried changing `value: any` to `value: valueof JWT` but that didn&#39;t work.

Ideally, `onChange(&#39;expire&#39;, 1337)` would fail because `1337` is not a Date type.

How can I change `value: any` to be the value of the given key?

Is there a `valueof` similar to `keyof` in TypeScript?

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 the following piece of code, which receives a history object as prop:

    const ChildComponent = ({ history }) =&gt; (
            &lt;div className={styles.body}&gt;
                &lt;div className={styles.cta}&gt;
                    &lt;FloatingActionButton onClick={() =&gt; history.push(routes[4].path)}&gt;
                        &lt;span&gt;Click me&lt;/span&gt;
                    &lt;/FloatingActionButton&gt;
                &lt;/div&gt;
            &lt;/div&gt;
    );

How do I add typecheck for this history prop, **which is received by wrapping it&#39;s parent with withRouter HOC**? One way I could think of is to write something like this:

    interface Props {
        history: {
            push(url: string): void;
        };
    }

But I&#39;m sure this is not the right way, because rest of the properties of the history object are being lost.

Can you suggest the right way of doing this?

**UPDATED the code based on @Oblosys&#39;s answer**

    import { withRouter, RouteComponentProps } from &quot;react-router-dom&quot;;

    interface Props extends RouteComponentProps&lt;any&gt; {
       /* Parent component&#39;s props*/
    }
    
    class Parent extends React.Component&lt;Props, {}&gt; {
        render() {
            return &lt;ChildComponent history={this.props.history} /&gt;;
        }
    }
    
    //Child component related stuff
    interface ChildComponentProps extends RouteComponentProps&lt;any&gt; {}
    
    const ChildComponent: React.SFC&lt;ChildComponentProps&gt; = (props) =&gt; (
      &lt;div className={styles.body}&gt;
         &lt;div className={styles.cta}&gt;
             &lt;FloatingActionButton onClick={() =&gt; history.push(routes[4].path)}&gt;
                &lt;span&gt;Click me&lt;/span&gt;
             &lt;/FloatingActionButton&gt;
         &lt;/div&gt;
       &lt;/div&gt;
    );

    function mapStateToProps(state: types.AppState) {
        /* related code */
    }
    
    function mapDispatchToProps(dispatch: Redux.Dispatch&lt;types.AppState&gt;{
        /* related code */
    }

    export default withRouter(connect(mapStateToProps, mapDispatchToProps)(Parent));

But, now I&#39;m getting the following error:

    Type &#39;{ history: History; }&#39; is not assignable to type &#39;ChildComponentProps&#39;.
        Property &#39;match&#39; is missing in type &#39;{ history: History; }&#39;

Content Type	Original Author	Original Content on Stackoverflow
Question	kechol	View Question on Stackoverflow
Solution 1 - Typescript	Titian Cernicova-Dragomir	View Answer on Stackoverflow
Solution 2 - Typescript	Deepak	View Answer on Stackoverflow

TypeScript and Iterator: Type 'IterableIterator<T>' is not an array type

Typescript Problem Overview

Typescript Solutions

Solution 1 - Typescript

Solution 2 - Typescript

Django or Django Rest Framework

How can I make rounded TextField in flutter?

Attributions