parse-query.ts

// use query-string package?
type QueryMap = {[key: string]: string};
const parseQuery = (queryString: string, param: string): string => {
  if (queryString.charAt(0) === '?') {
   queryString = queryString.substr(1);
  }
  const parts = queryString.split('&');
  const partsMap = parts.reduce((acc, part) => {
    const splitIndex = part.indexOf('=');
    if (splitIndex === -1) {
      return acc;
    }
    const queryKey = part.substring(0, splitIndex);
    const queryVal = part.substring(splitIndex + 1);
    acc[queryKey] = decodeURIComponent(queryVal);
    return acc;
  }, {} as QueryMap);
  return partsMap[param] ? partsMap[param] : '';
};

// navigate to http://[domain]?term=counter%20strike&device=ios
console.log(parseQuery(window.location.search, 'term'))
// => 'counter strike'