Get URL query string parameter values

getUrlParams.js

/**
 * Return the value of a URL parameter
 * @param url String 
 * @param key String
 */
const getUrlParam = (url, key) => {
  const results = new RegExp('[?&]' + key + '=([^&#]*)').exec(url)
  return results ? decodeURI(results[1]) : null
};

// Get the URL
const url = window.location.href

// Usage
if (getUrlParam(url, 'success')) {
  // Do something
}