Develop Reference

regex: get string in url login/test

I have a url
https://test.com/login/param2
how do I get the the second parameter "param2" from the url using REGEX?
the url can also be
https://test.com/login/param2/
So the regex should work for both urls.
I tried
var loc = window.location.href;
var locParts = loc.split('/');
and then looping through locParts, but that seems inefficient.
The "param2" can be have number, alphatical character from a-z, and a dash.

Use String#match method with regex /[^\/]+(?=\/?$)/.
var a = 'https://test.com/login/facebook',
b = 'https://test.com/login/facebook/';
var reg = /[^\/]+(?=\/?$)/;
console.log(
a.match(reg)[0],
b.match(reg)[0]
)
Or using String#split get last non-empty element.
var a = 'https://test.com/login/facebook',
b = 'https://test.com/login/facebook/';
var splita = a.split('/'),
splitb = b.split('/');
console.log(
splita.pop() || splita.pop(),
splitb.pop() || splitb.pop()
)

If you don't mind using JS only (so no regex), you can use this :
var lastParameter = window.location.href.split('/').slice(-1);
Basicaly, like you, I fetch the URL, split by the / character, but then I use the splice function to get teh last element of the split result array.

Regular expressions might be compact, but they're certainly not automatically efficient if you can do what you want without.
Here's how you can change your code:
var loc = 'https://test.com/login/facebook/'; // window.location.href;
var locParts = loc.split('/').filter(function(str) {return !!str});
var faceBookText = locParts.pop();
console.log(faceBookText);
The filter removes the last empty item you would get if the url ends with '/'. That's all you need, then just take the last item.

How can we split a string using starts with regular expression (/^myString/g)

I am having a case where i need to split given string using starts with regex (/^'searchString'/) which is not working such as
"token=123412acascasdaASDFADS".split('token=')
Here i want to extract the token value but as there might be some other possible parameters such as
"reset_token=SDFDFdsf12313ADADF".split('token=')
Here it also split the string with 'token=', Thats why i need to split the string using some regex which states that split the string where it starts with given string.
Thanks..
EDITED
Guys thanks for your valuable response this issue can be resolve using /\btoken=/ BUT BUT its does not work if 'token=' stored as a string into a variable such as
sParam = 'token=';
"token=123412acascasdaASDFADS".split(/\bsParam/);
This does not works.

You can use regex in split with word boundary:
"token=123412acascasdaASDFADS".split(/\btoken=/)
If token is stored in a variable then use RegExp constructor:
var sParam = "token";
var re = new RegExp("\\b" + sParam + "=");
Then use it:
var tokens = "token=123412acascasdaASDFADS".split( re );

This is the use case for the \b anchor:
\btoken=
It ensures there's no other word character before token (a word character being [a-zA-Z0-9_])

You need to split the string using the & parameter delimiter, then loop through those parameters:
var token;
$.each(params.split('&'), function() {
var parval = this.split('=');
if (parval[0] == "token") {
token = parval[1];
return false; // end the $.each loop
}
});
if you just use token= as the split delimiter, you'll include all the other parameters after it in the value.

It's not clear what you need, but this may be an idea to work with?
var reqstr = "token=12345&reset_token=SDFDFdsf12313ADADF&someval=foo"
.split(/[&=]/)
,req = [];
reqstr.map( function (v, i) {
if (i%2==0) {
var o = {};
o[/token/i.test(v) ? 'token' : v] = reqstr[i+1];
this.push(o);
} return v
}, req);
/* => req now contains:
[ { token: '12345' },
{ token: 'SDFDFdsf12313ADADF' },
{ someval: 'foo' } ]
*/

You can try with String#match() function and get the matched group from index 1
sample code
var re = /^token=(.*)$/;
var str = 'token=123412acascasdaASDFADS';
console.log('token=123412acascasdaASDFADS'.match('/^token=(.*)$/')[1]);
output:
123412acascasdaASDFADS
If token is dynamic then use RegExp
var token='token=';
var re = new RegExp("^"+token+"(.*)$");
var str = 'token=123412acascasdaASDFADS';
console.log(str.match(re)[1]);
Learn more...

With JavaScript, I need help concatenating a variable into a regular expression

I'm writing a JavaScript function to extract a segment out of a URL that appears to the right of a designated segment.
For instance, if this is my URL ...
mysite.com/cat/12/dog/34?test=123
... I would like to be able to pass 'cat' to the function and get 12, and later pass 'dog' to the function and have it return 34. I found this answer on StackOverflow to extract the URL segment, but it uses a string literal. And I'm having difficulty concatenating a passed in value.
jQuery to parse our a part of a url path
Here is my code. In this, rather than hard coding 'cat' into the pattern match, I would like to pass 'cat' into the segmentName parameter and have the regular expression match on that.
var url = "www.mysite.com/cat/12/dog/34?test=123";
alert(getNextSegmentAfterSegmentName(url, 'cat'));
function getNextSegmentAfterSegmentName(currentPath, segmentName) {
var nextSegment = "";
segmentName = segmentName.toLowerCase();
//var currentPath = window.location.pathname.toLowerCase();
if (currentPath.indexOf(segmentName) >= 0) {
var path = currentPath.split('?')[0]; // Strip querystring
// How do I concatenate segmentName into this?
var matches = path.match(/\/cat\/([^\/]+)/);
if (matches) {
nextSegment = matches[1];
}
}
return nextSegment;
}
Here is a jsfiddle example:
http://jsfiddle.net/Stormjack/2Ebsv/
Thanks for your help!

You need to create a RegExp object if you want to create regex using some string variable:
path.match(new RegExp("\/" + segmentName + "\/([^\/]+)"));

Extract values from href attribute string using JQuery

I would like to extract values from href attribute string using JQuery
$(this).attr("href")
will give me
?sortdir=ASC&sort=Vendor_Name
What i need is these values parsed into an array
myArray['sort']
myArray['sortdir']
Any ideas?
Thanks!
BTW , I saw somewhere else on SO the following similar idea to be used with a query string.
I could not tweak it for my needs just yet.
var urlParams = {};
(function () {
var match,
pl = /\+/g, // Regex for replacing addition symbol with a space
search = /([^&=]+)=?([^&]*)/g,
decode = function (s) { return decodeURIComponent(s.replace(pl, " ")); },
query = window.location.search.substring(1);
while (match = search.exec(query))
urlParams[decode(match[1])] = decode(match[2]);
})();

Try the following:
var href = $(this).attr("href")
href = href.replace('?', "").split('&');
var myArr = {};
$.each(href, function(i, v){
var s = v.split('=');
myArr[s[0]] = s[1];
});
DEMO

Try this
function getURLParameter(name, string) {
return decodeURI(
(RegExp(name + '=' + '(.+?)(&|$)').exec(string)||[,null])[1]
);
}
var string = $(this).attr("href");
alert(getURLParameter("sort",string));
Demo here http://jsfiddle.net/jbHa6/ You can change the var string value and play around.
EDIT
Removed the second example, since that code is not that good and does not serve the purpose.

Perhaps is there a better solution but to be quick I should have do something like that
var url = $(this).attr("href");
url = url.replace("?sortdir=", "");
url = url.replace("sort=", "");
myArray['sort'] = url.split("&")[1]; // Or use a temporary tab for your split
myArray['sortdir'] = url.split("&")[0];
That solution depends if your url is still like ?sortdir=ASC&sort=Vendor_Name

You could use jQuery BBQ's deparam function from here:
http://benalman.com/code/projects/jquery-bbq/examples/deparam/

javascript/jquery add trailing slash to url (if not present)

I'm making a small web app in which a user enters a server URL from which it pulls a load of data with an AJAX request.
Since the user has to enter the URL manually, people generally forget the trailing slash, even though it's required (as some data is appended to the url entered). I need a way to check if the slash is present, and if not, add it.
This seems like a problem that jQuery would have a one-liner for, does anyone know how to do this or should I write a JS function for it?

var lastChar = url.substr(-1); // Selects the last character
if (lastChar != '/') { // If the last character is not a slash
url = url + '/'; // Append a slash to it.
}
The temporary variable name can be omitted, and directly embedded in the assertion:
if (url.substr(-1) != '/') url += '/';
Since the goal is changing the url with a one-liner, the following solution can also be used:
url = url.replace(/\/?$/, '/');
If the trailing slash exists, it is replaced with /.
If the trailing slash does not exist, a / is appended to the end (to be exact: The trailing anchor is replaced with /).

url += url.endsWith("/") ? "" : "/"

I added to the regex solution to accommodate query strings:
http://jsfiddle.net/hRheW/8/
url.replace(/\/?(\?|#|$)/, '/$1')

This works as well:
url = url.replace(/\/$|$/, '/');
Example:
let urlWithoutSlash = 'https://www.example.com/path';
urlWithoutSlash = urlWithoutSlash.replace(/\/$|$/, '/');
console.log(urlWithoutSlash);
let urlWithSlash = 'https://www.example.com/path/';
urlWithSlash = urlWithSlash.replace(/\/$|$/, '/');
console.log(urlWithSlash);
Output:
https://www.example.com/path/
https://www.example.com/path/
It replaces either the trailing slash or no trailing slash with a trailing slash. So if the slash is present, it replaces it with one (essentially leaving it there); if one is not present, it adds the trailing slash.

You can do something like:
var url = 'http://stackoverflow.com';
if (!url.match(/\/$/)) {
url += '/';
}
Here's the proof: http://jsfiddle.net/matthewbj/FyLnH/

The URL class is pretty awesome - it helps us change the path and takes care of query parameters and fragment identifiers
function addTrailingSlash(u) {
const url = new URL(u);
url.pathname += url.pathname.endsWith("/") ? "" : "/";
return url.toString();
}
addTrailingSlash('http://example.com/slug?page=2');
// result: "http://example.com/slug/?page=2"
You can read more about URL on MDN

Before finding this question and it's answers I created my own approach. I post it here as I don't see something similar.
function addSlashToUrl() {
//If there is no trailing shash after the path in the url add it
if (window.location.pathname.endsWith('/') === false) {
var url = window.location.protocol + '//' +
window.location.host +
window.location.pathname + '/' +
window.location.search;
window.history.replaceState(null, document.title, url);
}
}

Not every URL can be completed with slash at the end. There are at least several conditions that do not allow one:
String after last existing slash is something like index.html.
There are parameters: /page?foo=1&bar=2.
There is link to fragment: /page#tomato.
I have written a function for adding slash if none of the above cases are present. There are also two additional functions for checking the possibility of adding slash and for breaking URL into parts. Last one is not mine, I've given a link to the original one.
const SLASH = '/';
function appendSlashToUrlIfIsPossible(url) {
var resultingUrl = url;
var slashAppendingPossible = slashAppendingIsPossible(url);
if (slashAppendingPossible) {
resultingUrl += SLASH;
}
return resultingUrl;
}
function slashAppendingIsPossible(url) {
// Slash is possible to add to the end of url in following cases:
// - There is no slash standing as last symbol of URL.
// - There is no file extension (or there is no dot inside part called file name).
// - There are no parameters (even empty ones — single ? at the end of URL).
// - There is no link to a fragment (even empty one — single # mark at the end of URL).
var slashAppendingPossible = false;
var parsedUrl = parseUrl(url);
// Checking for slash absence.
var path = parsedUrl.path;
var lastCharacterInPath = path.substr(-1);
var noSlashInPathEnd = lastCharacterInPath !== SLASH;
// Check for extension absence.
const FILE_EXTENSION_REGEXP = /\.[^.]*$/;
var noFileExtension = !FILE_EXTENSION_REGEXP.test(parsedUrl.file);
// Check for parameters absence.
var noParameters = parsedUrl.query.length === 0;
// Check for link to fragment absence.
var noLinkToFragment = parsedUrl.hash.length === 0;
// All checks above cannot guarantee that there is no '?' or '#' symbol at the end of URL.
// It is required to be checked manually.
var NO_SLASH_HASH_OR_QUESTION_MARK_AT_STRING_END_REGEXP = /[^\/#?]$/;
var noStopCharactersAtTheEndOfRelativePath = NO_SLASH_HASH_OR_QUESTION_MARK_AT_STRING_END_REGEXP.test(parsedUrl.relative);
slashAppendingPossible = noSlashInPathEnd && noFileExtension && noParameters && noLinkToFragment && noStopCharactersAtTheEndOfRelativePath;
return slashAppendingPossible;
}
// parseUrl function is based on following one:
// http://james.padolsey.com/javascript/parsing-urls-with-the-dom/.
function parseUrl(url) {
var a = document.createElement('a');
a.href = url;
const DEFAULT_STRING = '';
var getParametersAndValues = function (a) {
var parametersAndValues = {};
const QUESTION_MARK_IN_STRING_START_REGEXP = /^\?/;
const PARAMETERS_DELIMITER = '&';
const PARAMETER_VALUE_DELIMITER = '=';
var parametersAndValuesStrings = a.search.replace(QUESTION_MARK_IN_STRING_START_REGEXP, DEFAULT_STRING).split(PARAMETERS_DELIMITER);
var parametersAmount = parametersAndValuesStrings.length;
for (let index = 0; index < parametersAmount; index++) {
if (!parametersAndValuesStrings[index]) {
continue;
}
let parameterAndValue = parametersAndValuesStrings[index].split(PARAMETER_VALUE_DELIMITER);
let parameter = parameterAndValue[0];
let value = parameterAndValue[1];
parametersAndValues[parameter] = value;
}
return parametersAndValues;
};
const PROTOCOL_DELIMITER = ':';
const SYMBOLS_AFTER_LAST_SLASH_AT_STRING_END_REGEXP = /\/([^\/?#]+)$/i;
// Stub for the case when regexp match method returns null.
const REGEXP_MATCH_STUB = [null, DEFAULT_STRING];
const URL_FRAGMENT_MARK = '#';
const NOT_SLASH_AT_STRING_START_REGEXP = /^([^\/])/;
// Replace methods uses '$1' to place first capturing group.
// In NOT_SLASH_AT_STRING_START_REGEXP regular expression that is the first
// symbol in case something else, but not '/' has taken first position.
const ORIGINAL_STRING_PREPENDED_BY_SLASH = '/$1';
const URL_RELATIVE_PART_REGEXP = /tps?:\/\/[^\/]+(.+)/;
const SLASH_AT_STRING_START_REGEXP = /^\//;
const PATH_SEGMENTS_DELIMITER = '/';
return {
source: url,
protocol: a.protocol.replace(PROTOCOL_DELIMITER, DEFAULT_STRING),
host: a.hostname,
port: a.port,
query: a.search,
parameters: getParametersAndValues(a),
file: (a.pathname.match(SYMBOLS_AFTER_LAST_SLASH_AT_STRING_END_REGEXP) || REGEXP_MATCH_STUB)[1],
hash: a.hash.replace(URL_FRAGMENT_MARK, DEFAULT_STRING),
path: a.pathname.replace(NOT_SLASH_AT_STRING_START_REGEXP, ORIGINAL_STRING_PREPENDED_BY_SLASH),
relative: (a.href.match(URL_RELATIVE_PART_REGEXP) || REGEXP_MATCH_STUB)[1],
segments: a.pathname.replace(SLASH_AT_STRING_START_REGEXP, DEFAULT_STRING).split(PATH_SEGMENTS_DELIMITER)
};
}
There might also be several cases when adding slash is not possible. If you know some, please comment my answer.

For those who use different inputs: like http://example.com or http://example.com/eee. It should not add a trailling slash in the second case.
There is the serialization option using .href which will add trailing slash only after the domain (host).
In NodeJs,
You would use the url module like this:
const url = require ('url');
let jojo = url.parse('http://google.com')
console.log(jojo);
In pure JS, you would use
var url = document.getElementsByTagName('a')[0];
var myURL = "http://stackoverflow.com";
console.log(myURL.href);