Regex for finding string after the second occurrence of the character

February 1, 2024

The problem is to get from the string ‘https://myapp-ui.private.dev.mysubdom.eu’ the substring ‘dev.mysubdom.eu’ without the private.

So, in other words, I want to to get the substring after the occurrence of the second dot, the character ‘.’.

What I tried and works (so the next string after the occurrence of the first dot) : to extract the substring ‘dev.mysubdom.eu’ from ‘https://myapp-ui.private.dev.mysubdom.eu’ with the following portion of code:

function buildApiUrl() {
  const { hostname } = window.location;
  const suffix = hostname.replace(/^([^.])+/, '');

  return `${REACT_APP_API_PREFIX}${suffix || REACT_APP_API_SUFFIX}`;
}

Something else that I tried :

([^.]*).+ gives me ‘https://myapp-ui’ but not the desired outcome.

Any ideas ? Thanks !

>Solution :

you can do like this :

with Regex:

const url = 'https://myapp-ui.private.dev.mysubdom.eu';

// Use a regular expression to match the desired substring
const regex = /(?:[^.]+\.){2}(.+)/;
const match = url.match(regex);

// Extract the desired substring from the match
const desiredSubstring = match ? match[1] : '';
console.log(desiredSubstring)

without Regex:

const url = 'https://myapp-ui.private.dev.mysubdom.eu';

// Find the index of the first dot
const firstDotIndex = url.indexOf('.');

// Find the index of the second dot starting from the position after the first dot
const secondDotIndex = url.indexOf('.', firstDotIndex + 1);

// Extract the substring after the second dot
const desiredSubstring = url.substring(secondDotIndex + 1);

console.log(desiredSubstring);