Develop Reference

Regex NodeJS Javascript not applying

I have the following node.js code:
let regex = /^<#&\!?(\d+)>$/g;
console.log("Before match ", gettingargR) // gettingargR = <#&702877893436375100> or <#&!702877893436375100>
gettingargR = gettingargR.match(regex);
console.log("After match ", gettingargR)
console.log("After match value", gettingargR[0])
My target (expected) return is After match [ '702877893436375100' ] and After match value 702877893436375100
When I try to achieve this, console returns:
Before match <#&702877893436375100>
After match [ '<#&702877893436375100>' ]
After match value <#&702877893436375100>
Which means my regex isn't applying. How can I apply it to my string?

You need to remove the g flag from your regexp. The global flag turns off the capture group because it needs to return multiple values therefore the interpretation of the return array changes from a specification of the match to a list of complete matches.
let regex = /^<#&\!?(\d+)>$/; // remove the g flag
console.log("Before match ", gettingargR);
gettingargR = gettingargR.match(regex);
console.log("After match ", gettingargR)
console.log("After match value", gettingargR[1]); // capture group is element 1
Without the g flag the interpretation of the result is different. The return array now has the following structure:
[
'<#&702877893436375100>', // full match
'702877893436375100', // first capture group
// second capture group (if any),
// third capture group (if any),
// etc..
]

For matching all in the big file you can use exec function. For simple first match use reg without "g" flag:
Sample:
const matchAll = (str, reg) => {
let m;
let result = [];
do {
m = reg.exec(str);
if (m) {
result.push(m[1]);
}
} while (m);
return result;
};
gettingargR = `<#&702877893436375100>
<#&!702877893436375100>`;
let regex = /^<#&\!?(\d+)>$/gm;
console.log("After match ", matchAll(gettingargR, regex));

Maybe this could help.
const regex = /^<#&\!?(\d+)>$/g;
const str = `<#&702877893436375100>`;
let m;
while ((m = regex.exec(str)) !== null) {
// This is necessary to avoid infinite loops with zero-width matches
if (m.index === regex.lastIndex) {
regex.lastIndex++;
}
// The result can be accessed through the `m`-variable.
m.forEach((match, groupIndex) => {
console.log(`Found match, group ${groupIndex}: ${match}`);
});
}
Verified from https://regex101.com/

Regex to find the best matching subsetof a word

I have a list of coma separated words like cooler,bestwishes,congrat. I want to use regex to find the best matching word in this list. e.g Congratulations or Congrats matches congrat in the above list.
I have tried the regex below but it only works if the word in regex is the subset.
const regex = /[^,]*congratulation[^,]*/g;
const str = `this,cart,open,best-wishes,congrat`;
let m;
while ((m = regex.exec(str)) !== null) {
// This is necessary to avoid infinite loops with zero-width matches
if (m.index === regex.lastIndex) {
regex.lastIndex++;
}
// The result can be accessed through the `m`-variable.
m.forEach((match, groupIndex) => {
console.log(`Found match, group ${groupIndex}: ${match}`);
});
}
Is this possible using regex ?

Instead of searching for the target word's substring in a list of words you can search list of words in target word. That will reduce complexity and make it easier.
let words = ["cool","bestwishes","congrat","greatjob","welldone","kudos","thumbsup","keeprocking","rock","congrats"];
let word = "keeprockingbuddy";
let match = getMatchingWords(words,word);
console.log(match); // ["keeprocking", "rock"]
match = getMatchingWords(words,"Congratulations");
console.log(match); // ["congrat"]
function getMatchingWords(words,target){
let ans = [];
words.forEach((w)=>{
let found = target.match(new RegExp(w,"i"));
if(found){
ans.push(w);
}
})
ans = ans.length ? ans:"not found";
return ans;
}
Hope it answers your question.

Getting string parameters using regex

I'm trying to get a regex that can extract data from
BAYARPLN ke 116160029354, SUKSES. Hrg: 84.822. SN: TGK IMUM M SAMIN/R1/450/MAR,APR/Rp.89222/Adm6000/977-1071/047421CA414149E5CEC5. Saldo: 7
and I want to find this value like this...
977-1071
I tried to using parameter regex link this
"/(Adm6000)([^\7]+)/"
But I cant find the string regex 977-1071. Can I ask for help for this?

Did you try like this? see regex https://regex101.com/r/tccJ42/1
const regex = /\d+\-\d+/g; //use \d{3}\-\d{4} if you've digit limit
const str = `BAYARPLN ke 116160029354, SUKSES. Hrg: 84.822. SN: TGK IMUM M SAMIN/R1/450/MAR,APR/Rp.89222/Adm6000/977-1071/047421CA414149E5CEC5. Saldo: 7`;
let m;
while ((m = regex.exec(str)) !== null) {
// This is necessary to avoid infinite loops with zero-width matches
if (m.index === regex.lastIndex) {
regex.lastIndex++;
}
// The result can be accessed through the `m`-variable.
m.forEach((match, groupIndex) => {
console.log(`Found match, group ${groupIndex}: ${match}`);
});
}

If you want to match 977-1071 after /Adm6000/ you could first match /Adm6000/ and then capture in a group not a forward slash one or more times ([^/]+)
\/Adm6000\/([^/]+)
Your value 977-1071 will be in captured group 1:
const regex = /Adm6000\/([^/]+)/;
const str = `BAYARPLN ke 116160029354, SUKSES. Hrg: 84.822. SN: TGK IMUM M SAMIN/R1/450/MAR,APR/Rp.89222/Adm6000/977-1071/047421CA414149E5CEC5. Saldo: 7`;
let match = regex.exec(str);
console.log(match[1]);

Parse pipes when in JavaScript

I would like to split a string where the delimiter is a pipe.
But the pipe can be escaped and not splitted than.
example:
'aa|bb|cc'.split(/*??*/) // ['aa','bb','cc']
'aa\|aa|bb|cc|dd\|dd|ee'.split(/*??*/) // ['aa|aa', 'bb', 'cc', 'dd|dd', 'ee']
I try this, but it not work in javascript: (?<!\\)[\|]

Try this:
console.log('aa|bb|cc'.split('|'));
console.log('aa\|aa|bb|cc|dd\|dd|ee'.split('|'));

I assume that you want to skip splitting on escaped pipes. Use match instead:
console.log(
'aa\\|aa|bb|cc|dd\\|dd|ee'.match(/[^\\|]*(?:\\.[^\\|]*)*/g).filter(Boolean)
);

Hi the Regex I created
https://www.regexpal.com/index.php?fam=100132
What you need to do is concact the matches in an array
the code generated looks like this...
const regex = /(([^\\\|]+)\\?\|\2)|(\w+)/g;
const str = `aa\\|aa|bb|cc|dd\\|dd|ee`;
let m;
while ((m = regex.exec(str)) !== null) {
// This is necessary to avoid infinite loops with zero-width matches
if (m.index === regex.lastIndex) {
regex.lastIndex++;
}
// The result can be accessed through the `m`-variable.
m.forEach((match, groupIndex) => {
console.log(`Found match, group ${groupIndex}: ${match}`);
});
}
Hope this help you.

Best way to get the word right before a certain word in javascript

I have the following string
this is the string and THIS is the word I want
I've tried using a regex for this:
var to_search = "is"
var regex = "/\S+(?="+to_search+")/g";
var matches = string.match(regex);
And I wanted matches to contain "THIS" (word that comes after the second if) but it does not seem to be working
Any idea? Thanks

regex101.com is a really great site to test your regex and it even generates the code for you.
const regex = /\bis.*(this)/gi;
const str = `this is the string and THIS is the word I want`;
let m;
while ((m = regex.exec(str)) !== null) {
// This is necessary to avoid infinite loops with zero-width matches
if (m.index === regex.lastIndex) {
regex.lastIndex++;
}
// The result can be accessed through the `m`-variable.
m.forEach((match, groupIndex) => {
console.log(`Found match, group ${groupIndex}: ${match}`);
});
}

First you have to double backslashes when using the string form of regexes.
Second, you forgot whitespace in your pattern:
var regex = new RegExp("\\S+\\s+(?="+to_search+")", "g");