Develop Reference

Regex for filename at end of href attribute (replace filepath with filename)

I am trying to replace the filepath with just the filename using regex, and struggling.
I take a list of text like this:
xlink:href="file://C:\x\y & DRAWINGS\z - CONTROLLED\a \testsvg-A01.svg"
and i just want to output
xlink:href="testsvg-A01.svg"
I can get there with separate regex (javascript) with several bits of regex as such:
let inQuotes = hrefs[0].match(/"(.*?)"/gm);
inQuotes = inQuotes[0].match(/([^\\]+$)/gm);
inQuotes = inQuotes[0].replace(/"/g, "");
this will return just the filename, but i was wondering if there was a way to take this and replace the original text to the desired style.
EDIT:
i can get it for a single occurrance with this line of code:
let testHrefs = outText.match(/xlink:href="(.*?)"/gm)[0].match(/"(.*?)"/gm)[0].match(/([^\\]+$)/gm)[0].replace(/^/, 'xlink:href="');
but it looks awful and doesn't completely do what i want. Any advice?

You could use a regex to remove the text you don't want to keep (i.e. everything between the href=" and the filename:
let href = 'xlink:href="file://C:\\x\\y & DRAWINGS\\z - CONTROLLED\\a \\testsvg-A01.svg"';
console.log(href);
console.log(href.replace(/href=".*?([^\\\/]+)$/, 'href="$1'));
Note I've used [\\\/] to allow for Unix and Windows style filenames, if you only want Windows style filenames that can simply be [\\].

First, keep in mind that backslashes in strings need to be escaped, as the backslash itself is an escape character. You'll likely want to escape these as \\.
After doing this, you can make use of a positive look-behind on the \ with the regex (?<=\\)[^\\]*:
var xlink = "file://C:\\x\\y & DRAWINGS\\z - CONTROLLED\\a \\testsvg-A01.svg";
var regex = /(?<=\\)[^\\]*/gm;
console.log(xlink.match(regex));
This splits the string into each of the folders (which may be useful within itself), though if you exclusively want the filename, you can use xlink.match(regex)[4] (assuming the length is consistent), or xlink.match(regex)[xlink.match(regex).length - 1] if it isn't.
var xlink = "file://C:\\x\\y & DRAWINGS\\z - CONTROLLED\\a \\testsvg-A01.svg";
var regex = /(?<=\\)[^\\]*/gm;
console.log(xlink.match(regex)[xlink.match(regex).length - 1]);

Get base url from string with Regex and Javascript

I'm trying to get the base url from a string (So no window.location).
It needs to remove the trailing slash
It needs to be regex (No New URL)
It need to work with query parameters and anchor links
In other words all the following should return https://apple.com or https://www.apple.com for the last one.
https://apple.com?query=true&slash=false
https://apple.com#anchor=true&slash=false
http://www.apple.com/#anchor=true&slash=true&whatever=foo
These are just examples, urls can have different subdomains like https://shop.apple.co.uk/?query=foo should return https://shop.apple.co.uk - It could be any url like: https://foo.bar
The closer I got is with:
const baseUrl = url.replace(/^((\w+:)?\/\/[^\/]+\/?).*$/,'$1').replace(/\/$/, ""); // Base Path & Trailing slash
But this doesn't work with anchor links and queries which start right after the url without the / before
Any idea how I can get it to work on all cases?

You could add # and ? to your negated character class. You don't need .* because that will match until the end of the string.
For your example data, you could match:
^https?:\/\/[^#?\/]+
Regex demo
strings = [
"https://apple.com?query=true&slash=false",
"https://apple.com#anchor=true&slash=false",
"http://www.apple.com/#anchor=true&slash=true&whatever=foo",
"https://foo.bar/?q=true"
];
strings.forEach(s => {
console.log(s.match(/^https?:\/\/[^#?\/]+/)[0]);
})

You could use Web API's built-in URL for this. URL will also provide you with other parsed properties that are easy to get to, like the query string params, the protocol, etc.
Regex is a painful way to do something that the browser makes otherwise very simple.
I know that you asked about using regex, but in the event that you (or someone coming here in the future) really just cares about getting the information out and isn't committed to using regex, maybe this answer will help.
let one = "https://apple.com?query=true&slash=false"
let two = "https://apple.com#anchor=true&slash=false"
let three = "http://www.apple.com/#anchor=true&slash=true&whatever=foo"
let urlOne = new URL(one)
console.log(urlOne.origin)
let urlTwo = new URL(two)
console.log(urlTwo.origin)
let urlThree = new URL(three)
console.log(urlThree.origin)

const baseUrl = url.replace(/(.*:\/\/.*)[\?\/#].*/, '$1');

This will get you everything up to the .com part. You will have to append .com once you pull out the first part of the url.
^http.*?(?=\.com)
Or maybe you could do:
myUrl.Replace(/(#|\?|\/#).*$/, "")
To remove everything after the host name.

Extract characters in URL after certain character up to certain character

I'm trying to extract certain piece of a URL using regex (JavaScript) and having trouble excluding characters after a certain piece. Here's what I have so far:
URL: http://www.somesite.com/state-de
Using url.match(/\/[^\/]+$/)[0] I can extract the state-de like I want.
However when the URL becomes http://www.somesite.com/state-de?page=r and I do the same regex it pulls everything including the "?page=r" which I don't want. I want to only extract the state-de regardless of whats after it (looks like usually a "?" follows it)

This might work:
var arr = url.split("/")
arr[arr.length - 1].split("?")[0]

I'd recommend reading up on regular expressions in general. What you want to do here is make the regular expression stop when it hits the ? in the URL.
Using capturing groups to select which part of the match that you want might also be useful here.
Example:
url.match(/(\/[^\/?]+)(?:\?.*)?$/)[1]

I avoid overly complex RegExs when possible, so I tend to do this in multiple steps (with .replace()):
var stripped = url.replace(/[?#].*/, ''); // Strips anything after ? or #
You can now do the simpler transform to get the state, e.g.:
var state = stripped.split('/').pop()

If you want do it by regex try this one:
url.match(/https?:\/\/([a-z0-9-]+\.)+[a-z]+\/([a-z0-9_-])\/?(\?.*)?/)[1]
Or you could do it using JQuery:
var url = 'http://www.somesite.com/state-de?page=r#mark4';
// Create a special anchor element, set the URL to it
var a = $('<a>', { href:url } )[1];
console.log(a.hostname);
console.log(a.pathname);
console.log(a.search);
console.log(a.hash);

Regex to detect a string that contains a URL or file extension

I'm trying to create a small script that detects whether the string input is either:
1) a URL (which will hold a filename): 'http://ajax.googleapis.com/html5shiv.js'
2) just a filename: 'html5shiv.js'
So far I've found this but I think it just checks the URL and file extension. Is there an easy way to make it so it uses an 'or' check? I'm not very experienced with RegExp.
var myRegExp = /[^\\]*\.(\w+)$/i;
Thank you in advance.

How bout this regex?
(\.js)$
it checks the end of the line if it has a .js on it.
$ denotes end of line.
tested here.

Basically, to use 'OR' in regex, simply use the 'pipe' delimiter.
(aaa|bbb)
will match
aaa
or
bbb
For regex to match a url, I'd suggest the following:
\w+://[\w\._~:/?#\[\]#!$&'()*+,;=%]*
This is based on the allowed character set for a url.
For the file, what's your definition of a filename?
If you want to search for strings, that match "(at least) one to many non-fullstop characters, followed by a fullstop, followed by (at least) one to many non-fullstop characters", I'd suggest the following regex:
[^\.]+\.[^\.]+
And altogether:
(\w+://[\w\._~:/?#\[\]#!$&'()*+,;=%]*|[^\.]+\.[^\.]+)
Here's an example of working (in javascript): jsfiddle
You can test it out regex online here: http://gskinner.com/RegExr/

If it is for the purpose of flow control you can do the following:
var test = "http://ajax.googleapis.com/html5shiv.js";
// to recognize http & https
var regex = /^https?:\/\/.*/i;
var result = regex.exec(test);
if (result == null){
// no URL found code
} else {
// URL found code
}
For the purpose of capturing the file name you could use:
var test = "http://ajax.googleapis.com/html5shiv.js";
var regex = /(\w+\.\w+)$/i;
var filename = regex.exec(test);

Yes, you can use the alternation operator |. Be careful, though, because its priority is very low. Lower than sequencing. You will need to write things like /(cat)|(dog)/.
It's very hard to understand what you exactly want with so few use/test cases, but
(http://[a-zA-Z0-9\./]+)|([a-zA-Z0-9\.]+)
should give you a starting point.

If it's a URL, strip it down to the last part and treat it the same way as "just a filename".
function isFile(fileOrUrl) {
// This will return everything after the last '/'; if there's
// no forward slash in the string, the unmodified string is used
var filename = fileOrUrl.split('/').pop();
return (/.+\..+/).test(filename);
}

Try this:
var ajx = 'http://ajax.googleapis.com/html5shiv.js';
function isURL(str){
return /((\/\w+)|(^\w+))\.\w{2,}$/.test(str);
}
console.log(isURL(ajx));

Have a look at this (requires no regex at all):
var filename = string.indexOf('/') == -1
? string
: string.split('/').slice(-1)[0];

Here is the program!
<script>
var url="Home/this/example/file.js";
var condition=0;
var result="";
for(var i=url.length; i>0 && condition<2 ;i--)
{
if(url[i]!="/" && url[i]!="."){result= (condition==1)? (url[i]+result):(result);}
else{condition++;}
}
document.write(result);
</script>

Javascript Filename function / .html strip

Good Morning,
I'm using a function I got from another post here:
How to get the file name from a full path using JavaScript?
To return the current filename of a webpage
var url=window.location.pathname;
var filename = url.replace(/^.*[\\\/]/, '');
alert(filename);
and I was curious as to whether it is possible to strip the .html from the end while still using this syntax.

I think the easiest way will be
var filename = url.replace(/^.*[\\\/]/, '').replace(".html", "");

Either specify the extensions you want to manage, to be more restrictive, using:
.replace(/^.*[\/](.*)[.](html|jsp|php)/, '$1');
Either be more generic, using:
.replace(/^.*[\/](.*)[.][a-zA-Z0-9]{2,5}/, '$1');
The second one will allow extensions from 2 chars (e.g. .do) to 5 chars (e.g. .xhtml), which could also contain numbers (e.g. .php3).

You can use a capture clause in replace:
var url=window.location.pathname;
alert(url)
var filename = url.replace(/^.*[\\\/](.*).html$/, '$1');
alert(filename);