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How to take value using regular expressions?

I have such a string "Categ=All&Search=Jucs&Kin=LUU".How to get an array of values from this line [All,Jucs,LUU].
Here is an example
let x = /(\b\w+)$|(\b\w+)\b&/g;
let y = "Categories=All&Search=Filus";
console.log(y.match(x));
but I wanted no character &.

Since this looks like a URL query string, you can treat it as one and parse the data without needing a regex.
let query = "Categ=All&Search=Jucs&Kin=LUU",
parser = new URLSearchParams(query),
values = [];
parser.forEach(function(v, k){
values.push(v);
});
console.log(values);
Docs: https://developer.mozilla.org/en-US/docs/Web/API/URLSearchParams
Note: This may not work in IE, if that's something you care about.

Loop through all matches and take only the first group, ignoring the =
let x = /=([^&]+)/g;
let y = "Categories=All&Search=Filus";
let match;
while (match = x.exec(y)) {
console.log(match[1]);
}

To achieve expected result, use below option of using split and filter with index to separate Keys and values
1. Use split([^A-Za-z0-9]) to split string based on any special character other letters and numbers
2. Use Filter and index to get even or odd elements of array for keys and values
var str1 = "Categ=All&Search=Jucs&Kin=LUU";
function splitter(str, index){
return str.split(/[^A-Za-z0-9]/).filter((v,i)=>i%2=== index);
}
console.log(splitter(str1, 0)) //["Categ", "Search", "Kin"]
console.log(splitter(str1, 1))//["All", "Jucs", "LUU"]
codepen - https://codepen.io/nagasai/pen/yWMYwz?editors=1010

How to get the string just before specific character in JavaScript?

I have couple of strings like this:
Mar18L7
Oct13H0L7
I need to grab the string like:
Mar18
Oct13H0
Could any one please help on this using JavaScript? How can I split the string at the particular character?
Many Thanks in advance.

For var str = 'Mar18L7';
Try any of these:
str.substr(0, str.indexOf('L7'));
str.split('L7')[0]
str.slice(0, str.indexOf('L7'))
str.replace('L7', '')

Based on input that is given it I have created following function which can take n string in array and return the output in the format you have given. Check if this helps and if some use case is missed.
function generateStr(arr, splitStr) {
const processedStr = arr.map(value => value.split(splitStr)[0]);
return processedStr.join(" OR ");
}
console.log(generateStr(["Mar18L7", "Oct13H0L7"], "L7"));

You can use a regex like this
var data = ["Mar18L7", "Oct13H0L7"];
var regex = /^([a-zA-Z0-9]+)\L[a-zA-Z0-9]+$/;
var output = []
data.forEach(function(el){
var matches = el.match(regex);
output.push(matches[1]);
});
output variable will be equal to ['Mar18', 'Oct13H0'] and you can join all value usin the .join method on output array
var chain = output.join(" OR ");
// chain will be equal to "Mar18 OR Oct13H0"

How to rewrite this RegExp to not use deprecated API?

I have the following RegExp myRegexp, that matches numbers in a string:
var myRegexp = new RegExp('[0-9]+');
Then I have the following code that extracts numbers from a string and returns an array:
var string = '123:456';
var nums = new Array();
while(myRegexp.test(string)) {
nums.length++;
nums[nums.length - 1] = RegExp.lastMatch;
string = RegExp.rightContext;
}
Should return an array of two elements: "123", and "456".
However, RegExp.lastMatch and RegExp.rightContext are deprecated/non-standard API, and not portable. How can I rewrite this logic using portable JS API?
Thanks,

To match all numbers in a string, you'd simply use string.match(/\d/g); to match all single digits in a separate array entry, or string.match(/\d+/g); to match as numbers. There's no need for any of the things you've tried to use…
let string = "2kdkane2kdkie83kdkdk303ldld";
let match = string.match(/\d+/g);
let match1 = string.match(/\d/g);
console.log('numbers:', match);
console.log('single digits:', match1);

Use the g flag to perform a global match which will find all matches without having to repeatedly test the string.
let s = '123:456'
const regexp = new RegExp(/\d+/g);
let nums = s.match(regexp);
console.log(nums);

Get values from string through RegEx

I'm trying to get size values from a strings, which looks like:
https://example.com/eb5f16e5-9b3d-cfcd-19b0-75c6ace724e1/size/80x90/center/
I'm using match method and following RegEx:
'...'.match(/\/(\d+)x(\d+)\//g)
I hoped that the parentheses help to highlight the numbers:
But match returns only ["/80x90/"] without separate size values, like ["/80x90/", "80", "90"].
What am I'm doing wrong?
Here you can test my RegEx.

You don't need g modifier, without it you can get matching groups:
var url = 'https://example.com/eb5f16e5-9b3d-cfcd-19b0-75c6ace724e1/size/80x90/center/';
var res = url.match(/\/(\d+)x(\d+)\//);
console.log(res);

RegExp#exec will return all the captured group including the captured subexpression.
var url = 'https://example.com/eb5f16e5-9b3d-cfcd-19b0-75c6ace724e1/size/80x90/center/';
var patt = /\/(\d+)x(\d+)\//g;
var result = [];
while ((result = patt.exec(url)) !== null) {
console.log(result);
}

Using RegExp to substring a string at the position of a special character

Suppose I have a sting like this: ABC5DEF/G or it might be ABC5DEF-15 or even just ABC5DEF, it could be shorter AB7F, or AB7FG/H.
I need to create a javascript variable that contains the substring only up to the '/' or the '-'. I would really like to use an array of values to break at. I thought maybe to try something like this.
...
var srcMark = array( '/', '-' );
var whereAt = new RegExp(srcMark.join('|')).test.str;
alert("whereAt= "+whereAt);
...
But this returns an error: ReferenceError: Can't find variable: array
I suspect I'm defining my array incorrectly but trying a number of other things I've been no more successful.
What am I doing wrong?

Arrays aren't defined like that in JavaScript, the easiest way to define it would be with:
var srcMark = ['/','-'];
Additionally, test is a function so it must be called as such:
whereAt = new RegExp(srcMark.join('|')).test(str);
Note that test won't actually tell you where, as your variable suggests, it will return true or false. If you want to find where the character is, use String.prototype.search:
str.search(new RegExp(srcMark.join('|'));
Hope that helps.

You need to use the split method:
var srcMark = Array.join(['-','/'],'|'); // "-|/" or
var regEx = new RegExp(srcMark,'g'); // /-|\//g
var substring = "222-22".split(regEx)[0] // "222"
"ABC5DEF/G".split(regEx)[0] // "ABC5DEF"

From whatever i could understand from your question, using this RegExp /[/-]/ in split() function will work.
EDIT:
For splitting the string at all special characters you can use new RegExp(/[^a-zA-Z0-9]/) in split() function.
var arr = "ABC5DEF/G";
var ans = arr.split(/[/-]/);
console.log(ans[0]);
arr = "ABC5DEF-15";
ans = arr.split(/[/-]/);
console.log(ans[0]);
// For all special characters
arr = "AB7FG/H";
ans = arr.split(new RegExp(/[^a-zA-Z0-9]/));
console.log(ans[0]);

You can use regex with String.split.
It will look something like that:
var result = ['ABC5DEF/G',
'ABC5DEF-15',
'ABC5DEF',
'AB7F',
'AB7FG/H'
].map((item) => item.split(/\W+/));
console.log(result);
That will create an Array with all the parts of the string, so each item[0] will contain the text till the / or - or nothing.

If you want the position of the special character (non-alpha-numeric) you can use a Regular Expression that matches any character that is not a word character from the basic Latin alphabet. Equivalent to [^A-Za-z0-9_], that is: \W
var pattern = /\W/;
var text = 'ABC5DEF/G';
var match = pattern.exec(text);
var position = match.index;
console.log('character: ', match[0]);
console.log('position: ', position);