Develop Reference

Find file sequence with RegExp in Javascript

I have a simple question:
How do I use RegExp in Javascript to find strings that matches this filter:
*[0-9].png in order to filter out file sequences.
For example:
bird001.png
bird002.png
bird003.png
or
abc_1.png
abc_2.png
Should ignore strings like abc_1b.png and abc_abc.png
I'm going to use it in a getFiles function.
var regExp = new RegExp(???);
var files = dir.getFiles(regExp);
Thanks in advance!
EDIT:
If I have a defined string, let's say
var beginningStr = "bird";
How can I check if a string matches the filter
beginningStr[0-9].png
? And ideally beginningString without case sensitivity. So that the filter would allow Bird01 and bird02.
Thanks again!

Anything followed by [0-9] and ened by .png:
/^.*[0-9]\.png$/i
Or simply without begining (regex will find it itself):
/[0-9]\.png$/i

If I understood correctly, you need a regex that matches files with names which:
Begin with letters a-z, A-Z
Optionally followed with single _
Followed by one or more digits
Ending with .png
Regex for this is [a-zA-Z]_{0,1}+\d+\.png
You could try online regex builders which offer immediate explanation of what you write.

If I understood correctly,
var re = /\s[a-zA-Z]*[0-9]+\.png/g;
var filesArr = str.match(re);
filesArr.sort();// you can use own sort function
Please specify what is the dir variable

What RegEx would clean up this set of inputs?

I'm trying to figure out a RegEx that would match the following:
.../string-with-no-spaces -> string-with-no-spaces
or
string-with-no-spaces:... -> string-with-no-spaces
or
.../string-with-no-spaces:... -> string-with-no-spaces
where ... can be anything in these example strings:
example.com:8080/string-with-no-spaces:latest
string-with-no-spaces:latest
example.com:8080/string-with-no-spaces
string-with-no-spaces
and a bonus would be
http://example.com:8080/string-with-no-spaces:latest
and all would match string-with-no-spaces.
Is it possible for a single RegEx to cover all those cases?
So far I've gotten as far as /\/.+(?=:)/ but that not only includes the slash, but only works for case 3. Any ideas?
Edit: Also I should mention that I'm using Node.js, so ideally the solution should pass all of these: https://jsfiddle.net/ys0znLef/

How about:
(?:.*/)?([^/:\s]+)(?::.*|$)

Consider the following solution using specific regex pattern and String.match function:
var re = /(?:[/]|^)([^/:.]+?)(?:[:][^/]|$)/,
// (?:[/]|^) - passive group, checks if the needed string is preceded by '/' or is at start of the text
// (?:[:][^/]|$) - passive group, checks if the needed string is followed by ':' or is at the end of the text
searchString = function(str){
var result = str.match(re);
return result[1];
};
console.log(searchString("example.com:8080/string-with-no-spaces"));
console.log(searchString("string-with-no-spaces:latest"));
console.log(searchString("string-with-no-spaces"));
console.log(searchString("http://example.com:8080/string-with-no-spaces:latest"));
The output for all the cases above will be string-with-no-spaces

Here's the expression I've got... just trying to tweak to use the slash but not include it.
Updated result works in JS
\S([a-zA-Z0-9.:/\-]+)\S
//works on regexr, regex storm, & regex101 - tested with a local html file to confirm JS matches strings
var re = /\S([a-zA-Z0-9.:/\-]+)\S/;

Invalid regular expression in Javascript on Lookarounds

I'm having a problem with the regex that work in Expresso but not in the javascript code. I know that there are also two other question with the same topic, but can't figure out how to implement an alternative to my regex so that it will work also in javascript.
So my expression is:
((?<=\bvar)\s\w*\s?)=\s?function(\s*\([^)]*\))
Used in javascript like that:
var functionsReg = /((?<=\bvar)\s\w*\s?)=\s?function(\s*\([^)]*\))/gm;
var match = functionsReg.exec(func);
and I'm expecting to be able to get for the values for each regex group.
like:
var name = match[0];
var params = match[1];
I found out that the problem is from the (?<=\bvar)
But I can not find the alternative for this syntax because in the end I want to be able to access the text like in the below image.

Just match the var in a non-capture group:
/(?:var)\s+(\w+)\s*=\s*function(\s*\([^)]*\))/g

How to find in javascript with regular expression string from url?

Good evening, How can I find in javascript with regular expression string from url address for example i have url: http://www.odsavacky.cz/blog/wpcproduct/mikronebulizer/ and I need only string between last slashes (/ /) http://something.cz/something/string/ in this example word that i need is mikronebulizer. Thank you very much for you help.

You could use a regex match with a group.
Use this:
/([\w\-]+)\/$/.exec("http://www.odsavacky.cz/blog/wpcproduct/mikronebulizer/")[1];
Here's a jsfiddle showing it in action
This part: ([\w\-]+)
Means at least 1 or more of the set of alphanumeric, underscore and hyphen and use it as the first match group.
Followed by a /
And then finally the: $
Which means the line should end with this
The .exec() returns an array where the first value is the full match (IE: "mikronebulizer/") and then each match group after that.
So .exec()[1] returns your value: mikronebulizer

Simply:
url.match(/([^\/]*)\/$/);
Should do it.
If you want to match (optionally) without a trailing slash, use:
url.match(/([^\/]*)\/?$/);
See it in action here: http://regex101.com/r/cL3qG3

If you have the url provided, then you can do it this way:
var url = 'http://www.odsavacky.cz/blog/wpcproduct/mikronebulizer/';
var urlsplit = url.split('/');
var urlEnd = urlsplit[urlsplit.length- (urlsplit[urlsplit.length-1] == '' ? 2 : 1)];
This will match either everything after the last slash, if there's any content there, and otherwise, it will match the part between the second-last and the last slash.

Something else to consider - yes a pure RegEx approach might be easier (heck, and faster), but I wanted to include this simply to point out window.location.pathName.
function getLast(){
// Strip trailing slash if present
var path = window.location.pathname.replace(/\/$?/, '');
return path.split('/').pop();
}

Alternatively you could get using split:
var pieces = "http://www.odsavacky.cz/blog/wpcproduct/mikronebulizer/".split("/");
var lastSegment = pieces[pieces.length - 2];
// lastSegment == mikronebulizer

var url = 'http://www.odsavacky.cz/blog/wpcproduct/mikronebulizer/';
if (url.slice(-1)=="/") {
url = url.substr(0,url.length-1);
}
var lastSegment = url.split('/').pop();
document.write(lastSegment+"<br>");

Add regex to ignore /js /img and /css

I have this regular expression
// Look for /en/ or /en-US/ or /en_US/ on the URL
var matches = req.url.match( /^\/([a-zA-Z]{2,3}([-_][a-zA-Z]{2})?)(\/|$)/ );
Now with the above regular express it will cause the problem with the URL such as:
http://mydomain.com/css/bootstrap.css
or
http://mydomain.com/js/jquery.js
because my regular expression is to strip off 2-3 characters from A-Z or a-z
My question is how would I add in to this regular expression to not strip off anything with
js or img or css or ext
Without impacting the original one.
I'm not so expert on regular expression :(

Negative lookahead?
var matches = req.url.match(/^\/(?!(js|css))([a-zA-Z]{2,3}([-_][a-zA-Z]{2})?)(\/|$)/ );
\ not followed by js or css

First of all you have not defined what exactly you are searching for.
Define an array with lowercased common language codes (Common language codes)
This way you'll know what to look for.
After that, convert your url to lowercase and replace all '_' with '-' and search for every member of the array in the resulting string using indexOf().

Since you said you're using the regex to replace text, I changed it to a replace function. Also, you forced the regex to match the start of the string; I don't see how it would match anything with that. Anyway, here's my approach:
var result = req.url.replace(/\/([a-z]{2,3}([-_][a-z]{2})?)(?=\/|$)/i,
function(s,t){
switch(t){case"js":case"img":case"css":case"ext":return s;}
return "";
}
);