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Replace characters of a string matched by regex

I am in a situation to find the domain name of all valid URLs among a HTML page, replace these domain names with another domain name, but within the domain name, I need to do a 2nd replacement. For example, say the url https://www.example.com/path/to/somewhere is among the HTML page, I need to eventually transfer it into something like www-example-com.another.domain/path/to/somewhere.
I can do the first match and replace with the following code:
const regex = new RegExp('(https?:\/\/([^:\/\n\"\'?]+))', 'g');
txt = txt.replace(regex, "$1.another.domain");
but I have no idea how to do the second match and replace to replace the . into -. I wonder if there is any efficient way to finish this task. I tried to do something like the following but it does not work:
const regex = new RegExp('(https?:\/\/([^:\/\n\"\'?]+))', 'g');
txt = txt.replace(regex, "$1".replace(/'.'/g, '-') + ".another.domain");

Ok - I think I know what you're looking for. I'll explain what it's doing.
You 2 capture groups: the one before and the one after the first /.
You're taking the first capture group, and converting the . to -
You're adding via string .another.domain and then you're appending the 2nd capture group on it afterward
const address1 = 'https://www.example.com/path/to/somewhere';
const newDomain = "another.domain"
const pattern = /(https?:\/\/[^:\/\n\"\'?]+)(\/.*)/;
const matches = pattern.exec(address1);
const converted = matches[1].replace(/\./g, "-") + `.${newDomain}${matches[2]}`;
console.log(converted);

You can use the function version of String.prototype.replace() to have some more control over the specific replacements.
For example...
const txt = 'URL is https://www.example.com/path/to/somewhere'
const newTxt = txt.replace(/(https?:\/\/)([\w.]+)/g, (_, scheme, domain) =>
`${scheme}${domain.replace(/\./g, '-')}.another.domain`)
console.log(newTxt)
Here, scheme is the first capture group (https?:\/\/) and domain is the second ([\w.]+).
If you need a fancier domain matcher (as per your question), just substitute that part of the regex.

Split image path in javascript from first slash

I have the following path :
/data/2/444/test.text
or (without a slash at the start of the path)
data/2/444/test.text
I would like to return in JS the following result :
"/2/444/test.text"
I tried with the following: but I managed only to get the base name
new String(str).substring(str.lastIndexOf('/') + 1);

You can use a simple regex to remove the first directory in the path.
str.replace(/^\/?[^/]+\//, '/')
^\/? Optional slash at the beginning of string.
[^/]+\// match any non slash character until it encounter a slash
const input = ['/data/2/444/test.text', 'data/2/444/test.text', 'file.txt'];
const output = input.map(str => str.replace(/^\/?[^/]+\//, '/'))
console.log(output);
If you only want to replace /data from the beginning you can use:
^\/?data\/

lastIndexOf finds the last occurrence of a string within a string. When you use substring(x) on a string y, it will return the characters of y starting at x. So using lastIndexOf in this use case isn't what you want. You can achieve what you want by using indexOf (finding the first occurrence of a string within a string).
To account for the different formats of your input string (i.e. /data and data), you can just test for that:
function getPathWithoutData(str) {
var strWithoutSlash = str[0] === '/' ? str.substring(1) : str;
return strWithoutSlash.substring(strWithoutSlash.indexOf('/'));
}

You can easily do it without regexes and using slice and indexOf:
const getPath=path=>path.slice(path.indexOf('/',path[0]==="/"?1:0)-path.length);
console.log(getPath('/data/2/444/test.text'));
console.log(getPath('data/2/444/test.text'));
This checks if the first char is a / or not, and adjusts the indexOf accordingly to match either the second or first /. Also note how the subtraction gives a negative value, which gets the intended characters from the end, up to the /.
Of course you can do still do it with substring, as you were attempting, but with indexOf instead of lastIndexOf, because you want the 1st or 2nd / not the last one:
const getPath=path=>path.substring(path.indexOf('/',path[0]==="/"?1:0),path.length);
console.log(getPath('/data/2/444/test.text'));
console.log(getPath('data/2/444/test.text'));
It's worth mentioning that these may not be as robust as a regex, but are simple enough, and may fit your needs, depending on how the data can vary.

You could use String.prototype.split() and pass it a regex.
const paths = [
"/data/path/one",
"data/path/two"
];
const modifyPath = p => {
const [fallback, newPath] = p.split(/\/?data/);
return newPath || fallback;
}
console.log(paths.map(modifyPath));
Or you could use String.prototype.replace()
const paths = [
"/data/path/one",
"data/path/two",
];
const modifyPath = p => {
return p.replace(/\/?data(.*)/, '$1');
}
console.log(paths.map(modifyPath));

Way to replace substring that in regular expression with another

I want to know way to replace substring in url with new string.
https://pbs.twimg.com/media/DW7hPt9VAAAdKE7?format=jpg&name=small
after "&name=" they are many kind of size like
900x900,medium,360x360,small
let href = document.location.href;
if(!href.includes('&name=orig')){
if(href.includes(/900x900|medium|360x360|small/){ //if href have some size in regular expression
// I try to make it search for substring in regular expression
document.location.href = href.replace(/900x900|medium|360x360|small/,'orig');
}
else{ //if url don't have '&name=' like above
var adding = '&name=orig';
document.location.href = link+adding;
}
}
It not working
I don't want to write code to check all case like
if(href.includes('900x900')
if(href.includes('medium')
if(href.includes('360x360')
if(href.includes('small')
they are way to find match at once?

change if(href.includes(/900x900|medium|360x360|small/){ to
if(href.search(/900x900|medium|360x360|small/) !== -1){
as includes accepts the string not the regex.

Get a substring from a string for a regular expression in JavaScript

I have a string of the following form:
data-translate='view-7631b26ea80b1b601c313b15cc4e2ab03faedf30'>Avatar data
It can be in different languages, but in any case I need to get a string which is between the characters ' '
That is, in the example above, I need to get the following string:
view-7631b26ea80b1b601c313b15cc4e2ab03faedf30
Can I do this using the method string.replace(regexp, str) ?
I've highlighted the desired line using the following regular expression:
/'\b(.*)\b'/gm
Now, using the method string.replace I need to delete everything except that...
Got any suggestions?

Use match method.
var data = "data-translate='view-7631b26ea80b1b601c313b15cc4e2ab03faedf30'>Avatar data";
data = data.match(/'\b(.*)\b'/gm)

You have good solid anchor text in either side, so:
var match = /data-translate='([^']+)'/.exec(str);
var substr = match && match[1];
Live Example:
var str = "data-translate='view-7631b26ea80b1b601c313b15cc4e2ab03faedf30'>Avatar data";
var match = /data-translate='([^']+)'/.exec(str);
var substr = match && match[1];
document.body.innerHTML =
"<pre>Got: [" + substr + "]</pre>";
But again, as I said in a comment, using a simple regular expression to extract information from HTML is usually doomed to fail. For instance, you probably don't want to match this:
<p>The string is data-translate='view-7631b26ea80b1b601c313b15cc4e2ab03faedf30'</p>
...and yet, a simple regex solution will do exactly that. To properly handle HTML, you must use a proper HTML parser.

You can also try this one:
/\'([^\']+)\'/gm

Finding image url via using Regex

Any working Regex to find image url ?
Example :
var reg = /^url\(|url\(".*"\)|\)$/;
var string = 'url("http://domain.com/randompath/random4509324041123213.jpg")';
var string2 = 'url(http://domain.com/randompath/random4509324041123213.jpg)';
console.log(string.match(reg));
console.log(string2.match(reg));
I tied but fail with this reg
pattern will look like this, I just want image url between url(" ") or url( )
I just want to get output like http://domain.com/randompath/random4509324041123213.jpg
http://jsbin.com/ahewaq/1/edit

I'd simply use this expression:
/url.*\("?([^")]+)/
This returns an array, where the first index (0) contains the entire match, the second will be the url itself, like so:
'url("http://domain.com/randompath/random4509324041123213.jpg")'.match(/url.*\("?([^")]+)/)[1];
//returns "http://domain.com/randompath/random4509324041123213.jpg"
//or without the quotes, same return, same expression
'url(http://domain.com/randompath/random4509324041123213.jpg)'.match(/url.*\("?([^")]+)/)[1];
If there is a change that single and double quotes are used, you can simply replace all " by either '" or ['"], in this case:
/url.*\(["']?([^"')]+)/

Try this regexp:
var regex = /\burl\(\"?(.*?)\"?\)/;
var match = regex.exec(string);
console.log(match[1]);
The URL is captured in the first subgroup.

If the string will always be consistent, one option would be simply to remove the first 4 characters url(" and the last two "):
var string = 'url("http://domain.com/randompath/random4509324041123213.jpg")';
// Remove last two characters
string = string.substr(0, string.length - 2);
// Remove first five characters
string = string.substr(5, string.length);
Here's a working fiddle.
Benefit of this approach: You can edit it yourself, without asking StackOverflow to do it for you. RegEx is great, but if you don't know it, peppering your code with it makes for a frustrating refactor.