The actual code is:

    greet = &quot;...&quot;.toString.bind(&quot;hello world!&quot;)

Where the `...` in the string literal are the bytes `E2 80 AE`, which is the right-to-left override Unicode character, which causes everything after it to be displayed in reverse. It&#39;s used for writing right-to-left languages like Arabic or Hebrew.

[![hex editors are your friend][1]][1]


  [1]: https://i.stack.imgur.com/m9zTd.png

You have hidden characters which reverse the text. Here you can see the raw characters: https://www.soscisurvey.de/tools/view-chars.php

[![enter image description here][1]][1]


  [1]: https://i.stack.imgur.com/bj9N3.png

When moving from WSL1 to WSL2 many things change; apparently this applies to X11 forwarding as well.  
What steps do I need to make in order to use X11 forwarding with WSL2 on Windows 10 as I did with WSL1?

How to set up working X11 forwarding on WSL2

I have a simple Node/Express app made with Typescript.
And eslint give me the error

    Missing file extension &quot;ts&quot; for &quot;./lib/env&quot; import/extensions

Here is my .eslintrc file

        {
      &quot;extends&quot;: [
        &quot;airbnb&quot;,
        &quot;plugin:@typescript-eslint/recommended&quot;,
        &quot;prettier&quot;,
        &quot;prettier/react&quot;,
        &quot;plugin:import/errors&quot;,
        &quot;plugin:import/warnings&quot;,
        &quot;plugin:import/typescript&quot;
      ],
      &quot;parser&quot;: &quot;@typescript-eslint/parser&quot;,
      &quot;plugins&quot;: [&quot;@typescript-eslint&quot;, &quot;prettier&quot;, &quot;import&quot;],
      &quot;settings&quot;: {
        &quot;import/extensions&quot;: [&quot;.js&quot;, &quot;.jsx&quot;, &quot;.ts&quot;, &quot;.tsx&quot;],
        &quot;import/parsers&quot;: {
          &quot;@typescript-eslint/parser&quot;: [&quot;.ts&quot;, &quot;.tsx&quot;]
        },
        &quot;import/resolver&quot;: {
          &quot;typescript&quot;: {
            &quot;directory&quot;: &quot;./tsconfig.json&quot;
          },
          &quot;node&quot;: {
            &quot;extensions&quot;: [&quot;.js&quot;, &quot;.jsx&quot;, &quot;.ts&quot;, &quot;.tsx&quot;]
          }
        }
      },
      &quot;rules&quot;: {
        &quot;@typescript-eslint/indent&quot;: [2, 2],
        &quot;no-console&quot;: &quot;off&quot;,
        &quot;import/no-unresolved&quot;: [2, { &quot;commonjs&quot;: true, &quot;amd&quot;: true }],
        &quot;import/named&quot;: 2,
        &quot;import/namespace&quot;: 2,
        &quot;import/default&quot;: 2,
        &quot;import/export&quot;: 2
      }
    }

I have installed eslint-plugin-import &amp; eslint-import-resolver-typescript.
And I cannot figure out why, I got that error.

Typescript eslint - Missing file extension &quot;ts&quot; import/extensions

Recently a coworker showed this fragment of JavaScript code: 

```js
greet = &quot;‮&quot;.toString.bind(&quot;hello world!&quot;)
```

If you paste this inside the Developer Console and execute it will print a &quot;Hello, World!&quot; message:

```js
&gt;&gt; console.log(greet())
hello, world!
```

Another interesting thing I found is that if you paste the same `greet` code inside Node.js REPL it will automatically transpile it to a &quot;readable&quot; format.

How does this work? Why is this behaviour possible in a browser and why does Node.js automatically format it?





Why is this &quot;Hello, World!&quot; JavaScript code fragment recognized as an acceptable program instruction?

Recently a coworker showed this fragment of JavaScript code:
<pre><code class="hljs language-ini">greet = "‮".toString.bind("hello world!")
</code></pre>
If you paste this inside the Developer Console and execute it will print a "Hello, World!" message:
<pre><code class="hljs language-ruby">>> console.log(greet())
hello, world!
</code></pre>
Another interesting thing I found is that if you paste the same <code>greet</code> code inside Node.js REPL it will automatically transpile it to a "readable" format.
How does this work? Why is this behaviour possible in a browser and why does Node.js automatically format it?

I can&#39;t understand why variables act so strange when declared inside a function.

1. In the `first` function I declare with `let` the variables `b` and `c` with the value _10_:

        b = c = 10;

    In the `second` function I show:

        b + &quot;, &quot; + c

    And this shows:

        10, 10

2. Also in `first` function I declare `a` with value _10_:

        let a = b = c = 10;

    But in the `second` function it shows an error:

    &gt; Can&#39;t find variable: `a`

3. Now in the `first` function I declare `d` with value _20_:

        var d = 20;

    But in the `second` function it shows the same error as before, but with the variable `d`:

    &gt; Can&#39;t find variable: `d`

Example:

&lt;!-- begin snippet: js hide: false console: true babel: false --&gt;

&lt;!-- language: lang-js --&gt;

    function first() {
      let a = b = c = 10;
      var d = 20;
      second();
    }

    function second() {
      console.log(b + &quot;, &quot; + c); //shows &quot;10, 10&quot;

      try{ console.log(a); }  // Rreference error
      catch(e){ console.error(e.message) }

      try{ console.log(d); } // Reference error
      catch(e){ console.error(e.message) }
    }
    first()

&lt;!-- end snippet --&gt;



Why do some variables declared using let inside a function become available in another function, while others result in a reference error?

I am learning TypeScript and some bits are confusing to me. One bit is below:

```typescript
interface Props {
  name: string;
}

const PrintName: React.FC&lt;Props&gt; = (props) =&gt; {
  return (
    &lt;div&gt;
      &lt;p style={{ fontWeight: props.priority ? &quot;bold&quot; : &quot;normal&quot; }}&gt;
        {props.name}
      &lt;/p&gt;
    &lt;/div&gt;
  )
}

const PrintName2 = (props: Props) =&gt; {
  return (
    &lt;div&gt;
      &lt;p style={{ fontWeight: props.priority ? &quot;bold&quot; : &quot;normal&quot; }}&gt;
        {props.name}
      &lt;/p&gt;
    &lt;/div&gt;
  )
}
```

For both functional components above, I see TypeScript generates the same JS code. The `PrintName2` component seems more streamlined to me as far as readability. I wonder what&#39;s the difference between the two definitions and if anyone is using second type of React component?

TypeScript React.FC&lt;Props&gt; confusion

one application is running on port 3000 and I want to run another application on a different port of the default port. How I change this in React Next.js.
My **package.js** script is 

    &quot;scripts&quot;: {
        &quot;test&quot;: &quot;echo \&quot;Error: no test specified\&quot; &amp;&amp; exit 1&quot;,
        &quot;dev&quot;: &quot;next&quot;,
        &quot;build&quot;: &quot;next build&quot;,
        &quot;start&quot;: &quot;next start&quot;
      },

and start script command is
`npm run dev`

How to Set port in next.js

I need to connect to WebSockets server and log it&#39;s messages. With React class component I&#39;d put this logic in `componentDidMount` lifecycle hook and move on happily, but I&#39;m not sure how to properly implement it with hooks.

Here&#39;s my first attempt.
```js
import React, {useEffect} from &#39;react&#39;;

export default function AppWs() {
  useEffect(() =&gt; {
    let ws = new WebSocket(&#39;wss://ws.kraken.com/&#39;);
    ws.onopen = () =&gt; console.log(&#39;ws opened&#39;);
    ws.onclose = () =&gt; console.log(&#39;ws closed&#39;);

    ws.onmessage = e =&gt; {
      const message = JSON.parse(e.data);
      console.log(&#39;e&#39;, message);
    };

    return () =&gt; {
      ws.close();
    }
  }, []);

  return (
    &lt;div&gt;hooks + ws&lt;/div&gt;
  )
}
```
I added connection and log logic to `useEffect`, provided empty array with dependencies, and everything worked great. Until I needed to add `pause` state to pause logging.
```js
export default function AppWs() {
  const [isPaused, setPause] = useState(false);

  useEffect(() =&gt; {
    let ws = new WebSocket(&#39;wss://ws.kraken.com/&#39;);
    ws.onopen = () =&gt; console.log(&#39;ws opened&#39;);
    ws.onclose = () =&gt; console.log(&#39;ws closed&#39;);

    ws.onmessage = e =&gt; {
      if (isPaused) return;
      const message = JSON.parse(e.data);
      console.log(&#39;e&#39;, message);
    };

    return () =&gt; {
      ws.close();
    }
  }, []);

  return (
    &lt;div&gt;
      &lt;button onClick={() =&gt; setPause(!isPaused)}&gt;{isPaused ? &#39;Resume&#39; : &#39;Pause&#39;}&lt;/button&gt;
    &lt;/div&gt;
  )
}
```
ESLint started to yell at me that I should add `isPaused` state as a dependency to `useEffect`.  
Well, ok, done.  
But I noticed re-connection to WS server after every time I click the button. This is clearly not what I want.

My next iteration was to use two `useEffect`s: one for connection and one for message processing.
```js
export default function AppWs() {
  const [isPaused, setPause] = useState(false);
  const [ws, setWs] = useState(null);

  useEffect(() =&gt; {
    const wsClient = new WebSocket(&#39;wss://ws.kraken.com/&#39;);
    wsClient.onopen = () =&gt; {
      console.log(&#39;ws opened&#39;);
      setWs(wsClient);
    };
    wsClient.onclose = () =&gt; console.log(&#39;ws closed&#39;);

    return () =&gt; {
      wsClient.close();
    }
  }, []);

  useEffect(() =&gt; {
    if (!ws) return;

    ws.onmessage = e =&gt; {
      if (isPaused) return;
      const message = JSON.parse(e.data);
      console.log(&#39;e&#39;, message);
    };
  }, [isPaused, ws]);

  return (
    &lt;div&gt;
      &lt;button onClick={() =&gt; setPause(!isPaused)}&gt;{isPaused ? &#39;Resume&#39; : &#39;Pause&#39;}&lt;/button&gt;
    &lt;/div&gt;
  )
}
```
This works as expected, but I have a feeling that I miss something and this task can be solved easier, with one `useEffect`.
Please help to refactor the code on convince me that I&#39;m using React hooks in a proper way. Thanks!


Proper way of using React hooks + WebSockets

We&#39;re trying to use the new ways of exporting and importing modules for ES6 with Node.js. It&#39;s important for us to get the version number from the `package.json` file. The following code should do that:
```js
import {name, version} from &#39;../../package.json&#39;
```
However, on execution the following error is thrown:                       
    
    TypeError [ERR_UNKNOWN_FILE_EXTENSION]: Unknown file extension &quot;.json&quot; for T:\ICP\package.json imported from T:\ICP\src\controllers\about.js

Is there something we&#39;re missing?  
Is the extension `.json` not supported?  
Is there another way to retrieve this information using Node.js 13+?

Import &#39;.json&#39; extension in ES6 Node.js throws an error

I periodically run into the problem, having to spin up old Angular projects with deprecated dependencies of Angular.

Because I unsually run the latest Node.js version (at least lates LTS version) I often had the problem, that I wasn&#39;t able to get the old projects running.
I solved this by using a node version manager, but still I often have the problem that I&#39;m not sure what is the best Node.js version to use for Angular Version X.

Sadly the [official release notes](https://blog.angular.io/tagged/release%20notes) handle this topic shabbily and are not a true help, especially if you like to know as of which Angular Version you can&#39;t use a specific Node.js version anymore...

**Is there a complete compatibility list to check which Angular version is compatible with which Node.js version?**


Is there a compatibility list for Angular / Angular-CLI and Node.js?

When I tried install vue store front in my local but when I tried &quot;yarn install&quot; command I get following error. How can I solve this error? How can I solve this error?

    error /var/www/html/vue-storefront/node_modules/node-sass: Command failed.
    Exit code: 1
    Command: node scripts/build.js
    Arguments: 
    Directory: /var/www/html/vue-storefront/node_modules/node-sass
    Output:
    Building: /usr/bin/node /var/www/html/vue-storefront/node_modules/node-gyp/bin/node-gyp.js rebuild --verbose --libsass_ext= --libsass_cflags= --libsass_ldflags= --libsass_library=
    gyp info it worked if it ends with ok
    gyp verb cli [
    gyp verb cli   &#39;/usr/bin/node&#39;,
    gyp verb cli   &#39;/var/www/html/vue-storefront/node_modules/node-gyp/bin/node-gyp.js&#39;,
    gyp verb cli   &#39;rebuild&#39;,
    gyp verb cli   &#39;--verbose&#39;,
    gyp verb cli   &#39;--libsass_ext=&#39;,
    gyp verb cli   &#39;--libsass_cflags=&#39;,
    gyp verb cli   &#39;--libsass_ldflags=&#39;,
    gyp verb cli   &#39;--libsass_library=&#39;
    gyp verb cli ]
    gyp info using node-gyp@3.8.0
    gyp info using node@13.9.0 | linux | x64
    gyp verb command rebuild []
    gyp verb command clean []
    gyp verb clean removing &quot;build&quot; directory
    gyp verb command configure []
    gyp verb check python checking for Python executable &quot;/usr/bin/python3.6&quot; in the PATH
    gyp verb `which` succeeded /usr/bin/python3.6 /usr/bin/python3.6
    gyp ERR! configure error 
    gyp ERR! stack Error: Command failed: /usr/bin/python3.6 -c import sys; print &quot;%s.%s.%s&quot; % sys.version_info[:3];
    gyp ERR! stack   File &quot;&lt;string&gt;&quot;, line 1
    gyp ERR! stack     import sys; print &quot;%s.%s.%s&quot; % sys.version_info[:3];
    gyp ERR! stack                                ^
    gyp ERR! stack SyntaxError: invalid syntax
    gyp ERR! stack 
    gyp ERR! stack     at ChildProcess.exithandler (child_process.js:303:12)
    gyp ERR! stack     at ChildProcess.emit (events.js:321:20)
    gyp ERR! stack     at maybeClose (internal/child_process.js:1026:16)
    gyp ERR! stack     at Process.ChildProcess._handle.onexit (internal/child_process.js:286:5)
    gyp ERR! System Linux 4.15.0-88-generic
    gyp ERR! command &quot;/usr/bin/node&quot; &quot;/var/www/html/vue-storefront/node_modules/node-gyp/bin/node-gyp.js&quot; &quot;rebuild&quot; &quot;--verbose&quot; &quot;--libsass_ext=&quot; &quot;--libsass_cflags=&quot; &quot;--libsass_ldflags=&quot; &quot;--libsass_library=&quot;
    gyp ERR! cwd /var/www/html/vue-storefront/node_modules/node-sass
    gyp ERR! node -v v13.9.0



error /node_modules/node-sass: Command failed

Every time I try `npm install`. I get the following error. How do I fix it?

```
gyp: No Xcode or CLT version detected!
```

I am on `node -v → v8.8.0` &amp; `npm -v → v6.11.3`

I tried to run it on VSCode terminal and iTerm, but both ended up getting the same error. (both are updated to the latest version). The only new thing I did is updating my macOS to the latest version (Catalina 10.15.3 today).


```
$ npm install          Fri Mar  6 17:22:40 2020

&gt; fsevents@1.2.11 install /Users/synapse/Documents/synapsefi-dev-ui/node_modules/watchpack/node_modules/fsevents
&gt; node-gyp rebuild

No receipt for &#39;com.apple.pkg.CLTools_Executables&#39; found at &#39;/&#39;.

No receipt for &#39;com.apple.pkg.DeveloperToolsCLILeo&#39; found at &#39;/&#39;.

No receipt for &#39;com.apple.pkg.DeveloperToolsCLI&#39; found at &#39;/&#39;.

gyp: No Xcode or CLT version detected!
gyp ERR! configure error
gyp ERR! stack Error: `gyp` failed with exit code: 1
gyp ERR! stack     at ChildProcess.onCpExit (/Users/synapse/.nvm/versions/node/v8.8.0/lib/node_modules/npm/node_modules/node-gyp/lib/configure.js:344:16)
gyp ERR! stack     at emitTwo (events.js:125:13)
gyp ERR! stack     at ChildProcess.emit (events.js:213:7)
gyp ERR! stack     at Process.ChildProcess._handle.onexit (internal/child_process.js:200:12)
gyp ERR! System Darwin 19.3.0
gyp ERR! command &quot;/Users/synapse/.nvm/versions/node/v8.8.0/bin/node&quot; &quot;/Users/synapse/.nvm/versions/node/v8.8.0/lib/node_modules/npm/node_modules/node-gyp/bin/node-gyp.js&quot; &quot;rebuild&quot;
gyp ERR! cwd /Users/synapse/Documents/synapsefi-dev-ui/node_modules/watchpack/node_modules/fsevents
gyp ERR! node -v v8.8.0
gyp ERR! node-gyp -v v5.0.3
gyp ERR! not ok
npm WARN synapsefi-dev-ui@2.0.20 No repository field.
npm WARN The package country-data is included as both a dev and production dependency.
npm WARN The package react-dropzone is included as both a dev and production dependency.
npm WARN optional SKIPPING OPTIONAL DEPENDENCY: fsevents@1.2.11 (node_modules/watchpack/node_modules/fsevents):
npm WARN optional SKIPPING OPTIONAL DEPENDENCY: fsevents@1.2.11 install: `node-gyp rebuild`
npm WARN optional SKIPPING OPTIONAL DEPENDENCY: Exit status 1
```

`npm install` fails on node-gyp rebuild with `gyp: No Xcode or CLT version detected!`

When I am trying to load AWS credentials in my project it gives back an error.

When using credentials in plain text everything works good but when I am trying to use environment variables it&#39;s not working.



Error message. :

    Missing credentials in config, if using AWS_CONFIG_FILE, set AWS_SDK_LOAD_CONFIG=1


Here is my tried code :

    const AWS = require(&#39;aws-sdk&#39;);
    
    
    const SESConfig = {
        apiVersion: &quot;2010-12-01&quot;,
        accessKeyId: process.env.AWS_SECRET_KEY,
        accessSecretKey: process.env.AWS_SECRET_KEY,
        region: &quot;us-east-1&quot;
    }
    AWS.config.update(SESConfig);
    var sns = new AWS.SNS()
    var sns = new AWS.SNS();
    
    function sendSMS(to_number, message, cb) {
    
        sns.publish({
            Message: message,
            Subject: &#39;Admin&#39;,
            PhoneNumber:to_number
        }, cb);
      
      }
      
      // Example
      const PhoneNumberArray = [&#39;any mobile number&#39;]
      PhoneNumberArray.forEach(number =&gt; {
        sendSMS(number, &quot;Lorem Ipsum is simply dummy text of the printing and typesetting industry.&quot;, (err, result)=&gt;{
            console.log(&quot;RESULTS: &quot;,err,result)
          })
      })
     

Content Type	Original Author	Original Content on Stackoverflow
Question	devaerial	View Question on Stackoverflow
Solution 1 - Javascript	deceze	View Answer on Stackoverflow
Solution 2 - Javascript	feedy	View Answer on Stackoverflow

Why is this "Hello, World!" JavaScript code fragment recognized as an acceptable program instruction?

Javascript Problem Overview

Javascript Solutions

Solution 1 - Javascript

Solution 2 - Javascript

Typescript eslint - Missing file extension "ts" import/extensions

How to set up working X11 forwarding on WSL2

Attributions