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Filter out the required stuff from an input

So I'm using webSpeechSysthesis to make something that can take inputs and give out results on it with the commands that I have , one command is the "solve" something like "solve √45" and it'll give the answer
I cant figure out how do I separate the √45 and use it to calculate , in Speech synthesis the string that is said is stored in a variable "text"
I tried using replace() and replace the solve with nothing so that I only have numbers and operators but I only get the ' ' , nothing after it
Let word = "solve"
if(text.startsWith(word)){
let final = word.replaceAll(/\bsolve\b/g,'')
Console.log(final)
}

You should use let final = text.replaceAll(/\bsolve\b/g,'') instead of let final = word.replaceAll(/\bsolve\b/g,'').
let text = "solve √45";
let word = "solve";
if(text.startsWith(word)) {
let final = text.replaceAll(/\bsolve\b/g,'');
console.log(final);
};

You don't need to check if a word starts with solve, you can do this with regex as well using the ^ character. There is also no need to use the global flag with replaceAll.
let word = "solve √45";
let final = word.replace(/^solve\b /g, "");
console.log(final);

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 replace strings and get what I need in this case?

I am trying to replace a string with two sets of patterns. For example,
var pattern1 = '12345abcde/'; -> this is dynamic.
var myString = '12345abcde/hd123/godaddy_item'
my end goal is to get the value between two slashes which is hd123
I have
var stringIneed = myString.replace(pattern1, '').replace('godaddy_item','');
The above codes work but I think there is more elegant solution. Can anyone help me out on this? Thanks a lot!
UPDATE:
To be more clear, the pattern is per environement string. For example,
pattern1 could be something like:
https://myproject-development/item on development environment.
and
https://myproject/item on Production
myString could usually be like
https://myproject/item/hd123/godaddy_item
or
https://myproject-development/item/hd123/godaddy_item
and I need to get 'hd123' in my case.

I'd strongly suggest not using regular expressions for this, especially when simple String and Array methods will easily suffice and be far more understandable, such as:
// your question shows you can anticipate the sections you
// don't require, so put both/all of those portions into an
// array:
var unwanted = ['12345abcde', 'godaddy_item'],
// the string you wish to find the segment from:
myString = '12345abcde/hd123/godaddy_item',
// splitting the String into an array by splitting on the '/'
// characters, filtering that array using an arrow function
// in which the section is the current array-element of the
// array over which we're iterating; and here we keep those
// sections which are not found in the unwanted Array (the index
// an element not found in an Array is returned as -1):
desired = myString.split('/').filter(section => unwanted.indexOf(section) === -1);
console.log(desired); // ["hd123"]
Avoiding Arrow functions, for browsers not supporting ES6 (and having removed the code comments):
var unwanted = ['12345abcde', 'godaddy_item'],
myString = '12345abcde/hd123/godaddy_item',
desired = myString.split('/').filter(function (section) {
return unwanted.indexOf(section) === -1;
});
console.log(desired); // ["hd123"]
Or:
// the string to start with and filter:
var myString = '12345abcde/hd123/godaddy_item',
// splitting the string by the '/' characters and keeping those whose
// index is greater than 0 (so 'not the first') and also less than the
// length of the array-1 (since JS arrays are zero-indexed while length
// is 1-based):
wanted = myString.split('/').filter((section, index, array) => index > 0 && index < array.length - 1);
console.log(wanted); // ["hd123"]
JS Fiddle demo
If, however, the requisite string to be found is always the penultimate portion of the supplied string, then we can use Array.prototype.filter() to return only that portion:
var myString = '12345abcde/hd123/godaddy_item',
wanted = myString.split('/').filter((section, index, array) => index === array.length - 2);
console.log(wanted); // ["hd123"]
JS Fiddle demo.
References:
Array.prototype.filter().
Arrow functions.
String.prototype.split().

You can use
.*\/([^\/]+)\/.*$
Regex Demo
JS Demo
var re = /.*\/([^\/]+)\/.*$/g;
var str = '12345abcde/hd123/godaddy_item';
while ((m = re.exec(str)) !== null) {
document.writeln("<pre>" + m[1] + "</br>" + "</pre>");
}

You can easily do something like this:
myString.split('/').slice(-2)[0]
This will return the item directly, in simple most way.
var myString = 'https://myproject/item/hd123/godaddy_item';
console.log(myString.split('/').slice(-2)[0]); // hd123
myString = 'https://myproject-development/item/hd123/godaddy_item';
console.log(myString.split('/').slice(-2)[0]); // hd123

Try using match() as shown below:
var re = /\/(.*)\//;
var str = '12345abcde/hd123/godaddy_item';
var result = str.match(re);
alert(result[1]);

To say that David's answer will "easily suffice and be far more understandable" is a matter of opinion - this regex option (which includes building up the expression from variables) really couldn't be much simpler:
var pathPrefix = '12345abcde/'; //dynamic
var pathToTest = '12345abcde/hd123/godaddy_item';
var pattern = new RegExp(pathPrefix + '(.*?)\/')
var match = pattern.exec(pathToTest);
var result = (match != null && match[1] != null ? '[' + match[1] + ']' : 'no match was found.'); //[hd123]

Change occurrences of sum(something) to something_sum

Admittedly I'm terrible with RegEx and pattern replacements, so I'm wondering if anyone can help me out with this one as I've been trying now for a few hours and in the process of pulling my hair out.
Examples:
sum(Sales) needs to be converted to Sales_sum
max(Sales) needs to be converted to Sales_max
min(Revenue) needs to be converted to Revenue_min
The only available prefixed words will be sum, min, max, avg, xcount - not sure if this makes a difference in the solution.
Hopefully that's enough information to kind of show what I'm trying to do. Is this possible via RegEx?
Thanks in advance.

There are a few possible ways, for example :
var str = "min(Revenue)";
var arr = str.match(/([^(]+)\(([^)]+)/);
var result = arr[2]+'_'+arr[1];
result is then "Revenue_min".
Here's a more complex example following your comment, handling many matches and lowercasing the verb :
var str = "SUM(Sales) + MIN(Revenue)";
var result = str.replace(/\b([^()]+)\(([^()]+)\)/g, function(_,a,b){
return b+'_'+a.toLowerCase()
});
Result : "Sales_sum + Revenue_min"

Try with:
var input = 'sum(Sales)',
matches = input.match(/^([^(]*)\(([^)]*)/),
output = matches[2] + '_' + matches[1];
console.log(output); // Sales_sum
Also:
var input = 'sum(Sales)',
output = input.replace(/^([^(]*)\(([^)]*)\)/, '$2_$1');

You can use replace with tokens:
'sum(Sales)'.replace(/(\w+)\((\w+)\)/, '$2_$1')

Using a whitelist for your list of prefixed words:
output = input.replace(/\b(sum|min|max|avg|xcount)\((.*?)\)/gi,function(_,a,b) {
return b.toLowerCase()+"_"+a;
});
Added \b, a word boundary. This prevents something like "haxcount(xorz)" from becoming "haxorz_xcount"