getQueryParamsFromString.ts

const getQueryParamsFromString = (paramString: string) => (
  paramString ? paramString.split('&').map(splitToPair('=')) : null
);

const splitToPair = (separator: string) => (paramString: string) => {
  const [key, value = null] = paramString.split(separator);
  return {key, value};
}