Looks like Safari [doesn&#39;t support lookbehind yet](https://caniuse.com/js-regexp-lookbehind) (that is, your `(?&lt;=\/)`). One alternative would be to put the `/` that comes before in a non-captured group, and then extract only the first group (the content after the `/` and before the `#`).

    /(?:\/)([^#]+)(?=#*)/

Also, `(?=#*)` is odd - you probably want to lookahead for *something* (such as `#` or the end of the string), rather than a `*` quantifier (*zero* or more occurrences of `#`). It might be better to use something like

    /(?:\/)([^#]+)(?=#|$)/

or just omit the lookahead entirely (because the `([^#]+)` is greedy), depending on your circumstances.

In Windows 10, how do you install multiple, separate instances of Ubuntu in WSL? I&#39;d like separate instances for different work spaces. For instance one for Python development, one for Ruby development, one for .Net Core development, etc.  I know I could jam all of these into the same Ubuntu on WSL instance, but I&#39;d rather have a separate one for each of these scenarios.  Is this possible?

How do you install multiple, separate instances of Ubuntu in WSL?

So it appears with the advent of ASP.NET Core 2.1, Kestrel now automatically creates an HTTPS endpoint along side the HTTP one, and default project templates are setup to redirect from HTTP to HTTPS (which is easy enough to undo).

However my question is... how can I disable HTTPS entirely for my project. I&#39;ve read through the docs and played with a variety of config settings for HTTPS but nothing I do seems to allow me to turn it off and just run an HTTP project.

Am I crazy or just missing something. I would expect this to be super easy to do.

How do I disable HTTPS in ASP.NET Core 2.1 + Kestrel?

In my Javascript code, this regex `/(?&lt;=\/)([^#]+)(?=#*)/` works fine in Chrome, but in safari, I get: 

&gt; Invalid regular expression: invalid group specifier name

Any ideas?

Works in Chrome, but breaks in Safari: Invalid regular expression: invalid group specifier name /(?&lt;=\/)([^#]+)(?=#*)/

In my Javascript code, this regex <code>/(?&#x3C;=\/)([^#]+)(?=#*)/</code> works fine in Chrome, but in safari, I get:
> Invalid regular expression: invalid group specifier name
Any ideas?

I tried to specify the node engine in a package.json to accept both `8` and `10` version.

I tried to type this:

    &quot;engines&quot;: {
      &quot;node&quot;: &quot;8.x|10.x&quot;
    },

But running `yarn` results in:

&gt; The engine &quot;node&quot; is incompatible with this module. Expected version &quot;8.x|10.x&quot;

If I replace with:


    &quot;engines&quot;: {
      &quot;node&quot;: &quot;10.x&quot;
    },

... it works (i.e no error).

Is there a way to accept two versions of node engine in a `package.json`?


Node engine 8.x or 10.x in package.json

I&#39;m attempting to find an object in an array using `Array.prototype.includes`. Is this possible? I realize there is a difference between shallow and deep comparison. Is that the reason the below code returns false? I could not find a relevant answer for `Array.includes()`.

[![dev tools console][1]][1]

  [1]: https://i.stack.imgur.com/7pkYo.png

Array.includes() to find object in array

How can I make a **Material UI** react `Button` component act as a `Link` component from **react-router-dom** without losing it&#39;s original style? Like changing the route on click.

    import Button from &#39;@material-ui/core/Button&#39;;
    
    &lt;Button variant=&quot;contained&quot; color=&quot;primary&quot;&gt;
        About Page
    &lt;/Button&gt;

To something like this, but maintaining the original `Button` style:

    import Button from &#39;@material-ui/core/Button&#39;;
    import { Link } from &#39;react-router-dom&#39;;
        
    &lt;Button variant=&quot;contained&quot; color=&quot;primary&quot;&gt;
        &lt;Link to=&quot;/about&quot;&gt;
            About Page
        &lt;/Link&gt;
    &lt;/Button&gt;

How to make a Material UI react Button act as a react-router-dom Link?

I&#39;m having trouble figuring out how to have multiple pages in a Vue CLI project. Right now I have my home page with a few components and I want to create another page but I do not know how to do that. Am I supposed to create multiple html files where the index.html by default is? In a simple file structure with css js img folder and html files as pages I know that creating another html file means making another page. But I don&#39;t understand how this works with Vue CLI project.

I saw stuff like vue-router and &quot;pages&quot; in Vue documentation but I do not understand them very well. What are my alternatives? Is there a guide that explains that in detail, because I wasn&#39;t able to find any, let alone detailed. Would be very happy if you could help! Thank you!

multiple pages in Vue.js CLI

&gt; npm start

starts the react server on the default browser, which is Firefox for me. I like Firefox for browsing but prefer Chrome in web development for its developer tools. Is there a way to force &quot;npm start&quot; to start the server with Chrome, without changing my default browser to chrome? I am using Bash on Windows.

**Edit:** I used &quot;create-react-app&quot; to create my server and this adds a [script to &quot;packages.json&quot; file for &quot;npm start&quot;](https://i.imgur.com/j8DLTWU.png). The script starts the localhost server with the default browser. How do I modify the script added by &quot;create-react-app&quot; such that it starts with a different browser?

create-react-app: How do I &quot;npm start&quot; with a specific browser?

This probably isn&#39;t a VS Code-specific question but it&#39;s my tool of choice. 

I have a log file with a lot of lines containing the following:

`Company.Environment.Security.RightsBased.Policies.RightsUserAuthorizationPolicy`

Those are debug-level log records that clutter the file I&#39;m trying to process.  I&#39;m looking to remove the lines with that content. 

I&#39;ve looked into Regex but, unlike removing a blank line where you have the whole content in the search criteria (making find/replace easy), here I need to match from line break to line break on some criteria between the two, I think...

What are your thoughts on how criteria like that would work?

Visual Studio Code - Removing Lines Containing criteria

Why does this code output `02` in [tag:java-8] but `o2` in [tag:java-9] or above?

    &quot;o2&quot;.replaceAll(&quot;([oO])([^[0-9-]])&quot;, &quot;0$2&quot;)

Why does String.replaceAll() work differently in Java 8 from Java 9?

I stumbled across a surprising (to me) fact.

&lt;!-- begin snippet: js hide: false console: true babel: false --&gt;

&lt;!-- language: lang-js --&gt;

    console.log(&quot;asdf&quot;.replace(/.*/g, &quot;x&quot;));

&lt;!-- end snippet --&gt;

Why *two* replacements?  It seems any non-empty string without newlines will produce exactly two replacements for this pattern.  Using a replacement function, I can see that the first replacement is for the entire string, and the second is for an empty string.  

Why is &quot;asdf&quot;.replace(/.*/g, &quot;x&quot;) == &quot;xx&quot;?

I&#39;m a beginner to regex and I am trying to make an expression to find if there are two of the same digits next to each other, and the digit behind and in front of the pair is different.

For example,

123456678 should match as there is a double 6,

1234566678 should not match as there is no double with different surrounding numbers.
12334566 should match because there are two 3s.

So far i have this which works only with 1, and as long as the double is not at the start or end of the string, however I can deal with that by adding a letter at the start and end. 

```
^.*([^1]11[^1]).*$
```

I know i can use `[0-9]` instead of the 1s but the problem is having them all be the same digit. 

Thank you!

regex to find a pair of adjacent digits with different digits around them

I recently had a [SonarQube][1] rule (https://rules.sonarsource.com/java/RSPEC-4784) bring to my attention some performance issues which could be used as a denial of service against a Java regular expression implementation.

Indeed, the following Java test shows how slow the wrong regular expression can be:

```
    import org.junit.Test;

    public class RegexTest {

    @Test
    public void fastRegex1() {
        &quot;aaaaaaaaaaaaaaaaaaaaaaaaaaaabs&quot;.matches(&quot;(a+)b&quot;);
    }

    @Test
    public void fastRegex2() {
        &quot;aaaaaaaaaaaaaaaaaaaaaaaaaaaab&quot;.matches(&quot;(a+)+b&quot;);
    }

    @Test
    public void slowRegex() {
        &quot;aaaaaaaaaaaaaaaaaaaaaaaaaaaabs&quot;.matches(&quot;(a+)+b&quot;);
    }
}
```

As you can see, the first two tests are fast, the third one is incredibly slow (in Java 8)

[![Enter image description here][2]][2]

The same data and regex in Perl or Python, however, is not at all slow, which leads me to wonder why it is that this regular expression is so slow to evaluate in Java.

```
$ time perl -e &#39;&quot;aaaaaaaaaaaaaaaaaaaaaaaaaaaabs&quot; =~ /(a+)+b/ &amp;&amp; print &quot;$1\n&quot;&#39;
aaaaaaaaaaaaaaaaaaaaaaaaaaaa

real    0m0.004s
user    0m0.000s
sys     0m0.004s

$ time python3 -c &#39;import re; m=re.search(&quot;(a+)+b&quot;,&quot;aaaaaaaaaaaaaaaaaaaaaaaaaaaabs&quot;); print(m.group(0))&#39;
aaaaaaaaaaaaaaaaaaaaaaaaaaaab

real    0m0.018s
user    0m0.015s
sys     0m0.004s

```

What is it about the extra matching modifier `+` or trailing character `s` in the data which makes this regular expression so slow, and why is it only specific to Java?

  [1]: https://en.wikipedia.org/wiki/SonarQube
  [2]: https://i.stack.imgur.com/5bUNZ.png


Why is this regular expression so slow in Java?

&gt; ***Update at 2018.10.31***  
&gt;
&gt; *This bug has been fixed in iOS 12.1, have a good day~*

I found a problem with Array&#39;s value state in the newly released iOS&amp;nbsp;12 Safari, for example, code like this:

    &lt;!DOCTYPE html&gt;
    &lt;html&gt;
    &lt;head&gt;
        &lt;meta charset=&quot;utf-8&quot;&gt;
        &lt;meta name=&quot;viewport&quot; content=&quot;width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=0&quot;&gt;
        &lt;title&gt;iOS 12 Safari bugs&lt;/title&gt;
        &lt;script type=&quot;text/javascript&quot;&gt;
        window.addEventListener(&quot;load&quot;, function ()
        {
            let arr = [1, 2, 3, 4, 5];
            alert(arr.join());

            document.querySelector(&quot;button&quot;).addEventListener(&quot;click&quot;, function ()
            {
                arr.reverse();
            });
        });
        &lt;/script&gt;
    &lt;/head&gt;
    &lt;body&gt;
        &lt;button&gt;Array.reverse()&lt;/button&gt;
        &lt;p style=&quot;color:red;&quot;&gt;test: click button and refresh page, code:&lt;/p&gt;
    &lt;/body&gt;
    &lt;/html&gt;

After refreshing the page, the array&#39;s value is still reversed. Is this a bug or a feature of new Safari?

----------

Here is a demo page. Try to use it with iOS 12 Safari:
[https://abelyao.github.io/others/ios12-safari-bug.html][1]

  [1]: https://abelyao.github.io/others/ios12-safari-bug.html


Array state will be cached in iOS 12 Safari. Is it a bug or feature?

This is only an issue in Safari and looks like a Safari bug to me. Here is a [**fiddle**](https://jsfiddle.net/0scrgd9j/) with a simplified version of the issue.

When an image is in a nested flexbox element with a width set and `height: auto` it is being stretched... the auto height is not working. Does something extra need to be added for this to work in Safari?

&lt;!-- begin snippet: js hide: false console: true babel: false --&gt;

&lt;!-- language: lang-css --&gt;

    .container {
      display: flex;
      flex-direction: column;
    }

    .container section:first-child {
      display: flex;
      margin-bottom: 25px;
    }

    .container img {
      width: 125px;
      height: auto;
    }

&lt;!-- language: lang-html --&gt;

    &lt;div class=&quot;container&quot;&gt;
      &lt;section&gt;
        &lt;img src=&quot;https://via.placeholder.com/250&quot;&gt;
      &lt;/section&gt;
      &lt;section&gt;
        &lt;img src=&quot;https://via.placeholder.com/150&quot;&gt;
      &lt;/section&gt;
    &lt;/div&gt;

&lt;!-- end snippet --&gt;

I expect the height of the image to automatically be adjusted to maintain aspect ratio. This works in all browsers except Safari. In Safari the image is stretched and the auto height does not work.

Image stretching in flexbox in Safari

After Apple&#39;s iOS 13 release, I realized **`window.navigator.userAgent`** in Safari on iPad iOS 13 is same as on MacOS. Something like this:

```Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/13.0 Safari/605.1.15```

As you see, it&#39;s a wrong user-agent for iPad and there is no way to detect if the current device is an iDevice.

-----------------
After an initial research, I found a workaround for it:
&gt;Go to Settings -&gt; Safari -&gt; Request Desktop Website -&gt; All websites. You notice &quot;All websites&quot; is **enabled by default**. If you **disable** it and get window.navigator.userAgent the correct user agent is now displayed.

But I cannot ask each user to do this setting change for each device. So I tried to find another way and ended up by writing **the following code which checks if it&#39;s Safari, macOS, and touch-screen then the device should be an apple mobile device**, but I&#39;m wondering is there any better suggestion/way to detect the correct device name in Safari iOS 13?


```javascript
detectOs = function(){
   //returns OS name, like &quot;mac&quot;
};

//is Safari on an apple touch-screen device
isSafariInIdevice = function(){
   if (/Safari[\/\s](\d+\.\d+)/.test(windows.navigator.userAgent)) {
      return &#39;ontouchstart&#39; in window &amp;&amp; detectOs() === &quot;mac&quot;;      
   }
   return false;
};
```

Content Type	Original Author	Original Content on Stackoverflow
Question	techguy2000	View Question on Stackoverflow
Solution 1 - Javascript	CertainPerformance	View Answer on Stackoverflow

Works in Chrome, but breaks in Safari: Invalid regular expression: invalid group specifier name /(?<=\/)([^#]+)(?=#*)/

Javascript Problem Overview

Javascript Solutions

Solution 1 - Javascript

How do I disable HTTPS in ASP.NET Core 2.1 + Kestrel?

How do you install multiple, separate instances of Ubuntu in WSL?

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