Functional programming approach to parsing query strings in Typescript/ES6

functional-query-string-parser.ts

// Functional programming approach to parsing query strings in Typescript/ES6.
function parseQueryString(search: string) {
  return (search.startsWith('?') ? search.substring(1) : search)
    .split('&')
    .map(str => {
      const eqIdx = str.indexOf('=');
      if (eqIdx <= 0 || eqIdx >= str.length - 1) {
        return {};
      }

      const key = str.substring(0, eqIdx);
      const value = str.substring(eqIdx + 1, str.length);
      return {[key]: value};
    })
    .reduce((prev, next) => ({...prev, ...next}));
}