Pretty sure you could use `PropTypes.instanceOf(Date)`

I was trying to set default python version to `python3` in `Ubuntu 16.04`. By default it is `python2` (2.7). I followed below steps :  

    update-alternatives --remove python /usr/bin/python2
    update-alternatives --install /usr/bin/python python /usr/bin/python3

but I&#39;m getting the following error for the second statement,    

    rejeesh@rejeesh-Vostro-1015:~$ update-alternatives --install /usr/bin/python python /usr/bin/python3
    update-alternatives: --install needs &lt;link&gt; &lt;name&gt; &lt;path&gt; &lt;priority&gt;
    
    Use &#39;update-alternatives --help&#39; for program usage information.   

I&#39;m new to Ubuntu and Idon&#39;t know what I&#39;m doing wrong.



Unable to set default python version to python3 in ubuntu

I am getting this error from Angular 2

&gt; core.umd.js:5995 EXCEPTION: Uncaught (in promise): Error: Error in app/model_exposure_currencies/model_exposure_currencies.component.html:57:18
&gt; caused by: If ngModel is used within a form tag, either the name
&gt; attribute must be set or the form
&gt;           control must be defined as &#39;standalone&#39; in ngModelOptions.

   
Example 1:
```html
&lt;input [(ngModel)]=&quot;person.firstName&quot; name=&quot;first&quot;&gt;
```
Example 2:
```html
&lt;input [(ngModel)]=&quot;person.firstName&quot; [ngModelOptions]=&quot;{standalone: true}&quot;&gt; 
```

```html 
&lt;td *ngFor=&quot;let lag of ce.lags&quot;&gt;
    &lt;div class=&quot;form-group1&quot;&gt;
        &lt;input name=&quot;name&quot; [(ngModel)]=&quot;lag.name&quot; [ngModelOptions]=&quot;{standalone: true}&quot;  class=&quot;form-control&quot; pattern=&quot;[0-9]*(\.[0-9]+)?&quot; required&gt;
    &lt;/div&gt;
&lt;/td&gt;
```
This is how I use form tag:

```html
&lt;form #f=&quot;ngForm&quot; (ngSubmit)=&quot;onSubmit()&quot;&gt;
```

Angular2 If ngModel is used within a form tag, either the name attribute must be set or the form

**What is the currently preferred way to validate a `Date` prop in react?**

Right now I&#39;m using: `React.PropTypes.object`

This, however, is now failing the [forbid-prop-types](https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/forbid-prop-types.md) lint rule. Should I use a `shape` or is there some better way?

React prop validation for date objects

What is the currently preferred way to validate a <code>Date</code> prop in react?
Right now I'm using: <code>React.PropTypes.object</code>
This, however, is now failing the <a href="https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/forbid-prop-types.md" target="_blank" rel="noopener noreferrer">forbid-prop-types</a> lint rule. Should I use a <code>shape</code> or is there some better way?

I&#39;m new to both ES6 and React and I keep seeing arrow functions. Why is it that some arrow functions use curly braces after the fat arrow and some use parentheses?
For example:

    const foo = (params) =&gt; (
        &lt;span&gt;
            &lt;p&gt;Content&lt;/p&gt;
        &lt;/span&gt;
    );
vs.

    const handleBar = (e) =&gt; {
        e.preventDefault();
        dispatch(&#39;logout&#39;);
    };


Arrow function without curly braces

I&#39;m unsure how to get the values from 

    &lt;FormattedMessage {...messages.placeholderIntlText} /&gt;

into a placeholder format like input:

    &lt;input placeholder={&lt;FormattedMessage {...messages.placeholderIntlText} /&gt;} /&gt;

as it would return [Object object] in the actual placeholder. Is there a way to get the actual correct value?

React-Intl How to use FormattedMessage in input placeholder

I am trying to display list of images in a scrollview. Width should be 100%, while height should be automatic, keeping aspect ratio.

The searches I did pointed to various solutions which give fullscreen background style.

    const styles = StyleSheet.create({
        image: {
            width: null,
            height: 300,
            resizeMode: &#39;cover&#39;
        }
    });
    
    &lt;ScrollView style={{flex: 1}}&gt;
        &lt;Image style={styles.image} source={require(&#39;../../../images/collection-imag1.png&#39;)}/&gt;
        &lt;Image style={styles.image} source={require(&#39;../../../images/collection-imag2.png&#39;)}/&gt;
    &lt;/ScrollView&gt;

I have tried various combinations of width: null, height: null, flex: 1, alignSelf etc. The above solution is almost working, except the height is not dynamic. Parts of the image are not visible.

How to set image width to be 100% and height to be auto in react native?

Lets say I have:

    import Statement from &#39;./Statement&#39;;
    import SchoolDetails from &#39;./SchoolDetails&#39;;
    import AuthorizedStaff from &#39;./AuthorizedStaff&#39;;

    const MultiTab = () =&gt; (
      &lt;Tabs initialIndex={1} justify=&quot;start&quot; className=&quot;tablisty&quot;&gt;
        &lt;Tab title=&quot;First Title&quot; className=&quot;home&quot;&gt;
          &lt;Statement /&gt;
        &lt;/Tab&gt;
        &lt;Tab title=&quot;Second Title&quot; className=&quot;check&quot;&gt;
          &lt;SchoolDetails /&gt;
        &lt;/Tab&gt;
        &lt;Tab title=&quot;Third Title&quot; className=&quot;staff&quot;&gt;
          &lt;AuthorizedStaff /&gt;
        &lt;/Tab&gt;
      &lt;/Tabs&gt;
    );


Inside the Tabs component, `this.props` has the properties

    +Children[3]
    className=&quot;tablist&quot;
    justify=&quot;start&quot;

Children[0] (this.props.children) will look like 

    $$typeof:
    Symbol(react.element)
    _owner:ReactCompositeComponentWrapper
    _self:null
    _shadowChildren:Object
    _source:null
    _store:Object
    key:null
    props:Object
    ref:null
    type: Tab(props, context)
    __proto__
    Object

Children[0].props looks like 

    +Children (one element)
    className=&quot;home&quot;
    title=&quot;first title&quot;

Finally Children object looks like (this is what i want to pass):

    $$typeof:Symbol(react.element)
    _owner:ReactCompositeComponentWrapper
    _self:null
    _shadowChildren:undefined
    _source:null
    _store:
    key:null
    props:Object
    __proto__:Object
    **type: function Statement()**
    ref:null


The question is this, if I rewrite MultiTab like this

    &lt;Tabs initialIndex={1} justify=&quot;start&quot; className=&quot;tablisty&quot;&gt;
      &lt;Tab title=&quot;First Title&quot; className=&quot;home&quot; pass={Statement} /&gt;
      &lt;Tab title=&quot;Second Title&quot; className=&quot;check&quot; pass={SchoolDetails} /&gt;
      &lt;Tab title=&quot;Third Title&quot; className=&quot;staff&quot; pass={AuthorizedStaff} /&gt;
    &lt;/Tabs&gt;;
Inside the Tabs component

`this.props.children` looks the same as above.

`children[0].props` looks like 

    classname:&quot;home&quot;
    **pass: function Statement()**
    title: &quot;First title&quot;

I want the `pass` property to look like. Above just prints out the Statement function. 

    $$typeof:Symbol(react.element)
    _owner:ReactCompositeComponentWrapper
    _self:null
    _shadowChildren:undefined
    _source:null
    _store:
    key:null
    props:Object
    __proto__:Object
    **type: function Statement()**
    ref:null

This is a weird question, but long story I&#39;m using a library and this is what it comes down to.

Pass react component as props

I&#39;m new to React and I&#39;m trying to import a JSON `DATA` variable from an external file. I&#39;m getting the following error: 

&gt; Cannot find module &quot;./customData.json&quot;

Could some one help me? It works if I have my `DATA` variable in `index.js` but not when it&#39;s in an external JSON file.

#### index.js

    import React, {Component} from &#39;react&#39;;
    import ReactDOM from &#39;react-dom&#39;;
    import customData from &#39;./customData.json&#39;;
    import Profile from &#39;./components/profile&#39;;
    import Hobbies from &#39;./components/hobbies&#39;;

    class App extends Component {
	  render() {
        return (
          &lt;div&gt;
            &lt;Profile name={this.props.profileData.name}imgUrl={this.props.profileData.imgURL} /&gt;
            &lt;Hobbies hobbyList={this.props.profileData.hobbyList}/&gt;
          &lt;/div&gt;
        );
      }
    }

    ReactDOM.render(&lt;App profileData={DATA}/&gt;, document.querySelector(&#39;.container&#39;));

#### hobbies.js

    import React, {Component} from &#39;react&#39;;

    var Hobbies = React.createClass({
      render: function(){
        var hobbies = this.props.hobbyList.map(function(hobby, index){
            return (&lt;li key={index}&gt;{hobby}&lt;/li&gt;);
        });
        return (
        	&lt;div&gt;
	        	&lt;h5&gt;My hobbies:&lt;/h5&gt;
	            &lt;ul&gt;
	            	{hobbies}
	            &lt;/ul&gt;
            &lt;/div&gt;
        );
      } 
    });

    export default Hobbies;


#### profile.js

    import React from &#39;react&#39;;

    var Profile = React.createClass({
	render: function(){
		return (
			&lt;div&gt;
				&lt;h3&gt;{this.props.name}&lt;/h3&gt;
				&lt;img src={this.props.imgUrl} /&gt;
			&lt;/div&gt;
		)
	  }
    });

    export default Profile

#### customData.json

    var DATA = {    
        name: &#39;John Smith&#39;,
        imgURL: &#39;http://lorempixel.com/100/100/&#39;,
        hobbyList: [&#39;coding&#39;, &#39;writing&#39;, &#39;skiing&#39;]
    }

    export default DATA



Content Type	Original Author	Original Content on Stackoverflow
Question	David Weldon	View Question on Stackoverflow
Solution 1 - Reactjs	Alex Mcp	View Answer on Stackoverflow

React prop validation for date objects

Reactjs Problem Overview

Reactjs Solutions

Solution 1 - Reactjs

Angular2 If ngModel is used within a form tag, either the name attribute must be set or the form

Unable to set default python version to python3 in ubuntu

Attributions