I have ref=Apple
and my current regex is
var regex = /ref=(.+)/;
var ref = regex.exec(window.location.href);
alert(ref[0]);
but that includes the ref=
now, I also want to stop capturing characters if a & is at the end of the ref param. cause ref may not always be the last param in the url.
You'll want to split the url parameters, rather than using a regular expression.
Something like:
var get = window.location.href.split('?')[1];
var params = get.split('&');
for (p in params) {
var key = params[p].split('=')[0];
var value = params[p].split('=')[1];
if (key == 'ref') {
alert('ref is ' + value);
}
}
Use ref[1] instead.
This accesses what is captured by group 1 in your pattern.
Note that there's almost certainly a better way to do key/value parsing in Javascript than regex.
References
regular-expressions.info/Brackets for Capturing
You are using the ref wrong, you should use ref[1] for the (.+), ref[0] is the whole match.
If & is at the end, modify the regexp to /ref=([^&]+)/, to exclude &s.
Also, make sure you urldecode (unescape in JavaScript) the match.
Capture only word characters and numbers:
var regex = /ref=(\w+)/;
var ref = regex.exec(window.location.href);
alert(ref[1]);
Capture word characters, numbers, - and _:
var regex = /ref=([\w_\-]+)/;
var ref = regex.exec(window.location.href);
alert(ref[1]);
More information about Regular Expressions (the basics)
try this regex pattern ref=(.*?)&
This pattern will match anything after ref= and stop before '&'
To get the value of m just use following code:
var regex = /ref=(.*?)&/;
var ref = regex.exec(window.location.href);
alert(ref[1]);
Related
I want to add a (variable) tag to values with regex, the pattern works fine with PHP but I have troubles implementing it into JavaScript.
The pattern is (value is the variable):
/(?!(?:[^<]+>|[^>]+<\/a>))\b(value)\b/is
I escaped the backslashes:
var str = $("#div").html();
var regex = "/(?!(?:[^<]+>|[^>]+<\\/a>))\\b(" + value + ")\\b/is";
$("#div").html(str.replace(regex, "" + value + ""));
But this seem not to be right, I logged the pattern and its exactly what it should be.
Any ideas?
To create the regex from a string, you have to use JavaScript's RegExp object.
If you also want to match/replace more than one time, then you must add the g (global match) flag. Here's an example:
var stringToGoIntoTheRegex = "abc";
var regex = new RegExp("#" + stringToGoIntoTheRegex + "#", "g");
// at this point, the line above is the same as: var regex = /#abc#/g;
var input = "Hello this is #abc# some #abc# stuff.";
var output = input.replace(regex, "!!");
alert(output); // Hello this is !! some !! stuff.
JSFiddle demo here.
In the general case, escape the string before using as regex:
Not every string is a valid regex, though: there are some speciall characters, like ( or [. To work around this issue, simply escape the string before turning it into a regex. A utility function for that goes in the sample below:
function escapeRegExp(stringToGoIntoTheRegex) {
return stringToGoIntoTheRegex.replace(/[-\/\\^$*+?.()|[\]{}]/g, '\\$&');
}
var stringToGoIntoTheRegex = escapeRegExp("abc"); // this is the only change from above
var regex = new RegExp("#" + stringToGoIntoTheRegex + "#", "g");
// at this point, the line above is the same as: var regex = /#abc#/g;
var input = "Hello this is #abc# some #abc# stuff.";
var output = input.replace(regex, "!!");
alert(output); // Hello this is !! some !! stuff.
JSFiddle demo here.
Note: the regex in the question uses the s modifier, which didn't exist at the time of the question, but does exist -- a s (dotall) flag/modifier in JavaScript -- today.
If you are trying to use a variable value in the expression, you must use the RegExp "constructor".
var regex = "(?!(?:[^<]+>|[^>]+<\/a>))\b(" + value + ")\b";
new RegExp(regex, "is")
I found I had to double slash the \b to get it working. For example to remove "1x" words from a string using a variable, I needed to use:
str = "1x";
var regex = new RegExp("\\b"+str+"\\b","g"); // same as inv.replace(/\b1x\b/g, "")
inv=inv.replace(regex, "");
You don't need the " to define a regular expression so just:
var regex = /(?!(?:[^<]+>|[^>]+<\/a>))\b(value)\b/is; // this is valid syntax
If value is a variable and you want a dynamic regular expression then you can't use this notation; use the alternative notation.
String.replace also accepts strings as input, so you can do "fox".replace("fox", "bear");
Alternative:
var regex = new RegExp("/(?!(?:[^<]+>|[^>]+<\/a>))\b(value)\b/", "is");
var regex = new RegExp("/(?!(?:[^<]+>|[^>]+<\/a>))\b(" + value + ")\b/", "is");
var regex = new RegExp("/(?!(?:[^<]+>|[^>]+<\/a>))\b(.*?)\b/", "is");
Keep in mind that if value contains regular expressions characters like (, [ and ? you will need to escape them.
I found this thread useful - so I thought I would add the answer to my own problem.
I wanted to edit a database configuration file (datastax cassandra) from a node application in javascript and for one of the settings in the file I needed to match on a string and then replace the line following it.
This was my solution.
dse_cassandra_yaml='/etc/dse/cassandra/cassandra.yaml'
// a) find the searchString and grab all text on the following line to it
// b) replace all next line text with a newString supplied to function
// note - leaves searchString text untouched
function replaceStringNextLine(file, searchString, newString) {
fs.readFile(file, 'utf-8', function(err, data){
if (err) throw err;
// need to use double escape '\\' when putting regex in strings !
var re = "\\s+(\\-\\s(.*)?)(?:\\s|$)";
var myRegExp = new RegExp(searchString + re, "g");
var match = myRegExp.exec(data);
var replaceThis = match[1];
var writeString = data.replace(replaceThis, newString);
fs.writeFile(file, writeString, 'utf-8', function (err) {
if (err) throw err;
console.log(file + ' updated');
});
});
}
searchString = "data_file_directories:"
newString = "- /mnt/cassandra/data"
replaceStringNextLine(dse_cassandra_yaml, searchString, newString );
After running, it will change the existing data directory setting to the new one:
config file before:
data_file_directories:
- /var/lib/cassandra/data
config file after:
data_file_directories:
- /mnt/cassandra/data
Much easier way: use template literals.
var variable = 'foo'
var expression = `.*${variable}.*`
var re = new RegExp(expression, 'g')
re.test('fdjklsffoodjkslfd') // true
re.test('fdjklsfdjkslfd') // false
Using string variable(s) content as part of a more complex composed regex expression (es6|ts)
This example will replace all urls using my-domain.com to my-other-domain (both are variables).
You can do dynamic regexs by combining string values and other regex expressions within a raw string template. Using String.raw will prevent javascript from escaping any character within your string values.
// Strings with some data
const domainStr = 'my-domain.com'
const newDomain = 'my-other-domain.com'
// Make sure your string is regex friendly
// This will replace dots for '\'.
const regexUrl = /\./gm;
const substr = `\\\.`;
const domain = domainStr.replace(regexUrl, substr);
// domain is a regex friendly string: 'my-domain\.com'
console.log('Regex expresion for domain', domain)
// HERE!!! You can 'assemble a complex regex using string pieces.
const re = new RegExp( String.raw `([\'|\"]https:\/\/)(${domain})(\S+[\'|\"])`, 'gm');
// now I'll use the regex expression groups to replace the domain
const domainSubst = `$1${newDomain}$3`;
// const page contains all the html text
const result = page.replace(re, domainSubst);
note: Don't forget to use regex101.com to create, test and export REGEX code.
var string = "Hi welcome to stack overflow"
var toSearch = "stack"
//case insensitive search
var result = string.search(new RegExp(toSearch, "i")) > 0 ? 'Matched' : 'notMatched'
https://jsfiddle.net/9f0mb6Lz/
Hope this helps
I have a url
https://test.com/login/param2
how do I get the the second parameter "param2" from the url using REGEX?
the url can also be
https://test.com/login/param2/
So the regex should work for both urls.
I tried
var loc = window.location.href;
var locParts = loc.split('/');
and then looping through locParts, but that seems inefficient.
The "param2" can be have number, alphatical character from a-z, and a dash.
Use String#match method with regex /[^\/]+(?=\/?$)/.
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.
This doesn't return what I, or regex101, expects:
var myString = "Accel World|http://www.anime-planet.com/anime/accel-worldAh! My Goddess|http://www.anime-planet.com/anime/ah-my-goddess";
var reg = /[^|]*/g;
var regResponse = reg.exec(myString);
console.log(regResponse);
according to regex101, this should match everything except '|' and return it yet it only matches the first string, Accel World, as opposed to everything but '|'.
How do I fix this?
Exec will only return one result at a time (subsequent calls will return the rest, but you also need to use the + instead of *)
You could use the myString.match(reg) htough to get all results in one go.
var myString = "Accel World|http://www.anime-planet.com/anime/accel-worldAh! My Goddess|http://www.anime-planet.com/anime/ah-my-goddess";
var reg = /[^|]+/g;
var regResponse = myString.match(reg);
console.log(regResponse);
You need to loop .exec() to retrieve all matches. The documentation says
If your regular expression uses the "g" flag, you can use the exec()
method multiple times to find successive matches in the same string.
var reg = /[^|]+/g;
while(regResponse = reg.exec(myString)) {
console.log(regResponse);
}
Try a "+" instead of the "*"
So,
var reg = /[^|]+/g;
I am using the function match for a search engine, so whenever a user types a search-string I take that string and use the match function on an array containing country names, but it doesn't seem to work.
For example if I do :
var string = "algeria";
var res = string.match(/alge/g); //alge is what the user would have typed in the search bar
alert(res);
I get a string res = "alge": //thus verifying that alge exists in algeria
But if I do this, it returns null, why? and how can I make it work?
var regex = "/alge/g";
var string = "algeria";
var res = string.match(regex);
alert(res);
To make a regex from a string, you need to create a RegExp object:
var regex = new RegExp("alge", "g");
(Beware that unless your users will be typing actual regular expressions, you'll need to escape any characters that have special meaning within regular expressions - see Is there a RegExp.escape function in Javascript? for ways to do this.)
You don't need quotes around the regex:
var regex = /alge/g;
Remove the quotes around the regex.
var regex = /alge/g;
var string = "algeria";
var res = string.match(regex);
alert(res);
found the answer, the match function takes a regex object so have to do
var regex = new RegExp(string, "g");
var res = text.match(regex);
This works fine
I have a URL that looks like http://mysite.com/#id/Blah-blah-blah, it's used for Ajax-ey bits. I want to use substring() or substr() to get the id part. ID could be any combination of any length of letters and numbers.
So far I have got:
var hash = window.location.hash;
alert(hash.substring(1)); // remove #
Which removes the front hash, but I'm not a JS coder and I'm struggling a bit. How can I remove all of it except the id part? I don't want anything after and including the final slash either (/Blah-blah-blah).
Thanks!
Jack
Now, this is a case where regular expressions will make sense. Using substring here won't work because of the variable lengths of the strings.
This code will assume that the id part wont contain any slashes.
var hash = "#asdfasdfid/Blah-blah-blah";
hash.match(/#(.+?)\//)[1]; // asdfasdfid
The . will match any character and
together with the + one or more characters
the ? makes the match non-greedy so that it will stop at the first occurence of a / in the string
If the id part can contain additional slashes and the final slash is the separator this regex will do your bidding
var hash = "#asdf/a/sdfid/Blah-blah-blah";
hash.match(/#(.+?)\/[^\/]*$/)[1]; // asdf/a/sdfid
Just for fun here are versions not using regular expressions.
No slashes in id-part:
var hash = "#asdfasdfid/Blah-blah-blah",
idpart = hash.substr(1, hash.indexOf("/"));
With slashes in id-part (last slash is separator):
var hash = "#asdf/a/sdfid/Blah-blah-blah",
lastSlash = hash.split("").reverse().indexOf("/") - 1, // Finding the last slash
idPart = hash.substring(1, lastSlash);
var hash = window.location.hash;
var matches = hash.match(/#(.+?)\//);
if (matches.length > 1) {
alert(matches[1]);
}
perhaps a regex
window.location.hash.match(/[^#\/]+/)
Use IndexOf to determine the position of the / after id and then use string.substr(start,length) to get the id value.
var hash = window.location.hash;
var posSlash = hash.indexOf("/", 1);
var id = hash.substr(1, posSlash -1)
You need ton include some validation code to check for absence of /
This one is not a good aproach, but you wish to use if you want...
var relUrl = "http://mysite.com/#id/Blah-blah-blah";
var urlParts = [];
urlParts = relUrl.split("/"); // array is 0 indexed, so
var idpart = = urlParts[3] // your id will be in 4th element
id = idpart.substring(1) //we are skipping # and read the rest
The most foolproof way to do it is probably the following:
function getId() {
var m = document.location.href.match(/\/#([^\/&]+)/);
return m && m[1];
}
This code does not assume anything about what comes after the id (if at all). The id it will catch is anything except for forward slashes and ampersands.
If you want it to catch only letters and numbers you can change it to the following:
function getId() {
var m = document.location.href.match(/\/#([a-z0-9]+)/i);
return m && m[1];
}